<br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the ‘<samp><spanclass="samp">sed</span></samp>’ script <var>pattern</var> to be applied to the names
of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to
consist of one or more basic ‘<samp><spanclass="samp">sed</span></samp>’ editing commands, separated by
semicolons. For example, if you want the ‘<samp><spanclass="samp">gcc</span></samp>’ program name to be
transformed to the installed program <samp><spanclass="file">/usr/local/bin/myowngcc</span></samp> and
the ‘<samp><spanclass="samp">g++</span></samp>’ program name to be transformed to
<samp><spanclass="file">/usr/local/bin/gspecial++</span></samp> without changing other program names,
<p>As a last shortcoming, none of the installed Ada programs are
transformed yet, which will be fixed in some time.
<br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the
installation directory for local include files. The default is
<samp><spanclass="file">/usr/local</span></samp>. Specify this option if you want the compiler to
search directory <samp><var>dirname</var><spanclass="file">/include</span></samp> for locally installed
header files <em>instead</em> of <samp><spanclass="file">/usr/local/include</span></samp>.
<p>You should specify <samp><spanclass="option">--with-local-prefix</span></samp><strong>only</strong> if your
site has a different convention (not <samp><spanclass="file">/usr/local</span></samp>) for where to put
site-specific files.
<p>The default value for <samp><spanclass="option">--with-local-prefix</span></samp> is <samp><spanclass="file">/usr/local</span></samp>
regardless of the value of <samp><spanclass="option">--prefix</span></samp>. Specifying
<samp><spanclass="option">--prefix</span></samp> has no effect on which directory GCC searches for
local header files. This may seem counterintuitive, but actually it is
logical.
<p>The purpose of <samp><spanclass="option">--prefix</span></samp> is to specify where to <em>install
GCC</em>. The local header files in <samp><spanclass="file">/usr/local/include</span></samp>—if you put
any in that directory—are not part of GCC. They are part of other
programs—perhaps many others. (GCC installs its own header files in
another directory which is based on the <samp><spanclass="option">--prefix</span></samp> value.)
<p>Both the local-prefix include directory and the GCC-prefix include
directory are part of GCC's “system include” directories. Although these
two directories are not fixed, they need to be searched in the proper
order for the correct processing of the include_next directive. The
local-prefix include directory is searched before the GCC-prefix
include directory. Another characteristic of system include directories
is that pedantic warnings are turned off for headers in these directories.
<p>Some autoconf macros add <samp><spanclass="option">-I </span><var>directory</var></samp> options to the
compiler command line, to ensure that directories containing installed
packages' headers are searched. When <var>directory</var> is one of GCC's
system include directories, GCC will ignore the option so that system
directories continue to be processed in the correct order. This
may result in a search order different from what was specified but the
directory will still be searched.
<p>GCC automatically searches for ordinary libraries using
<samp><spanclass="env">GCC_EXEC_PREFIX</span></samp>. Thus, when the same installation prefix is
used for both GCC and packages, GCC will automatically search for
both headers and libraries. This provides a configuration that is
easy to use. GCC behaves in a manner similar to that when it is
installed as a system compiler in <samp><spanclass="file">/usr</span></samp>.
<p>Sites that need to install multiple versions of GCC may not want to
use the above simple configuration. It is possible to use the
<samp><spanclass="option">--program-prefix</span></samp>, <samp><spanclass="option">--program-suffix</span></samp> and
<samp><spanclass="option">--program-transform-name</span></samp> options to install multiple versions
into a single directory, but it may be simpler to use different prefixes
and the <samp><spanclass="option">--with-local-prefix</span></samp> option to specify the location of the
site-specific files for each version. It will then be necessary for
users to specify explicitly the location of local site libraries
(e.g., with <samp><spanclass="env">LIBRARY_PATH</span></samp>).
<p>The same value can be used for both <samp><spanclass="option">--with-local-prefix</span></samp> and
<samp><spanclass="option">--prefix</span></samp> provided it is not <samp><spanclass="file">/usr</span></samp>. This can be used
to avoid the default search of <samp><spanclass="file">/usr/local/include</span></samp>.
<p><strong>Do not</strong> specify <samp><spanclass="file">/usr</span></samp> as the <samp><spanclass="option">--with-local-prefix</span></samp>!
The directory you use for <samp><spanclass="option">--with-local-prefix</span></samp><strong>must not</strong>
contain any of the system's standard header files. If it did contain
them, certain programs would be miscompiled (including GNU Emacs, on
certain targets), because this would override and nullify the header
file corrections made by the <samp><spanclass="command">fixincludes</span></samp> script.
<p>Indications are that people who use this option use it based on mistaken
ideas of what it is for. People use it as if it specified where to
install part of GCC. Perhaps they make this assumption because
installing GCC creates the directory.
<br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on
the target platform. Unlike GCC 2.95.x and earlier, shared libraries
are enabled by default on all platforms that support shared libraries.
<p>If a list of packages is given as an argument, build shared libraries
only for the listed packages. For other packages, only static libraries
will be built. Package names currently recognized in the GCC tree are
‘<samp><spanclass="samp">libgcc</span></samp>’ (also known as ‘<samp><spanclass="samp">gcc</span></samp>’), ‘<samp><spanclass="samp">libstdc++</span></samp>’ (not
<var>libexec</var> defaults to <samp><var>exec-prefix</var><spanclass="file">/libexec</span></samp>;
<var>exec-prefix</var> defaults to <var>prefix</var>, which
defaults to <samp><spanclass="file">/usr/local</span></samp> unless overridden by the
<samp><spanclass="option">--prefix=</span><var>pathname</var></samp> switch described above. <var>target</var>
is the target system triple, such as ‘<samp><spanclass="samp">sparc-sun-solaris2.7</span></samp>’, and
<var>version</var> denotes the GCC version, such as 3.0.
<li>If the target system is the same that you are building on, check
operating system specific directories (e.g. <samp><spanclass="file">/usr/ccs/bin</span></samp> on
Sun Solaris 2).
<li>Check in the <samp><spanclass="env">PATH</span></samp> for a tool whose name is prefixed by the
target system triple.
<li>Check in the <samp><spanclass="env">PATH</span></samp> for a tool whose name is not prefixed by the
target system triple, if the host and target system triple are
the same (in other words, we use a host tool if it can be used for
the target as well).
</ul>
<p>You may want to use <samp><spanclass="option">--with-as</span></samp> if no assembler
is installed in the directories listed above, or if you have multiple
assemblers installed and want to choose one that is not found by the
above rules.
<br><dt><code><aname="with_002dgnu_002dld"></a>--with-gnu-ld</code><dd>Same as <ahref="#with-gnu-as"><samp><spanclass="option">--with-gnu-as</span></samp></a>
but for the linker.
<br><dt><code>--with-ld=</code><var>pathname</var><dd>Same as <ahref="#with-as"><samp><spanclass="option">--with-as</span></samp></a>
but for the linker.
<br><dt><code>--with-stabs</code><dd>Specify that stabs debugging
information should be used instead of whatever format the host normally
uses. Normally GCC uses the same debug format as the host system.
<p>On MIPS based systems and on Alphas, you must specify whether you want
GCC to create the normal ECOFF debugging format, or to use BSD-style
stabs passed through the ECOFF symbol table. The normal ECOFF debug
format cannot fully handle languages other than C. BSD stabs format can
handle other languages, but it only works with the GNU debugger GDB.
<p>Normally, GCC uses the ECOFF debugging format by default; if you
prefer BSD stabs, specify <samp><spanclass="option">--with-stabs</span></samp> when you configure GCC.
<p>No matter which default you choose when you configure GCC, the user
can use the <samp><spanclass="option">-gcoff</span></samp> and <samp><spanclass="option">-gstabs+</span></samp> options to specify explicitly
the debug format for a particular compilation.
<p><samp><spanclass="option">--with-stabs</span></samp> is meaningful on the ISC system on the 386, also, if
<samp><spanclass="option">--with-gas</span></samp> is used. It selects use of stabs debugging
information embedded in COFF output. This kind of debugging information
supports C++ well; ordinary COFF debugging information does not.
<p><samp><spanclass="option">--with-stabs</span></samp> is also meaningful on 386 systems running SVR4. It
selects use of stabs debugging information embedded in ELF output. The
C++ compiler currently (2.6.0) does not support the DWARF debugging
information normally used on 386 SVR4 platforms; stabs provide a
workable alternative. This requires gas and gdb, as the normal SVR4
tools can not generate or interpret stabs.
<br><dt><code>--disable-multilib</code><dd>Specify that multiple target
libraries to support different target variants, calling
conventions, etc. should not be built. The default is to build a
predefined set of them.
<p>Some targets provide finer-grained control over which multilibs are built
<br><dt><code>--with-cpu=</code><var>cpu</var><dt><code>--with-cpu-32=</code><var>cpu</var><dt><code>--with-cpu-64=</code><var>cpu</var><dd>Specify which cpu variant the compiler should generate code for by default.
<br><dt><code>--with-schedule=</code><var>cpu</var><dt><code>--with-arch=</code><var>cpu</var><dt><code>--with-arch-32=</code><var>cpu</var><dt><code>--with-arch-64=</code><var>cpu</var><dt><code>--with-tune=</code><var>cpu</var><dt><code>--with-tune-32=</code><var>cpu</var><dt><code>--with-tune-64=</code><var>cpu</var><dt><code>--with-abi=</code><var>abi</var><dt><code>--with-fpu=</code><var>type</var><dt><code>--with-float=</code><var>type</var><dd>These configure options provide default values for the <samp><spanclass="option">-mschedule=</span></samp>,
<samp><spanclass="option">-march=</span></samp>, <samp><spanclass="option">-mtune=</span></samp>, <samp><spanclass="option">-mabi=</span></samp>, and <samp><spanclass="option">-mfpu=</span></samp>
options and for <samp><spanclass="option">-mhard-float</span></samp> or <samp><spanclass="option">-msoft-float</span></samp>. As with
<samp><spanclass="option">--with-cpu</span></samp>, which switches will be accepted and acceptable values
of the arguments depend on the target.
<br><dt><code>--with-mode=</code><var>mode</var><dd>Specify if the compiler should default to <samp><spanclass="option">-marm</span></samp> or <samp><spanclass="option">-mthumb</span></samp>.
<br><dt><code>--with-fpmath=</code><var>isa</var><dd>This options sets <samp><spanclass="option">-mfpmath=sse</span></samp> by default and specifies the default
ISA for floating-point arithmetics. You can select either ‘<samp><spanclass="samp">sse</span></samp>’ which
enables <samp><spanclass="option">-msse2</span></samp> or ‘<samp><spanclass="samp">avx</span></samp>’ which enables <samp><spanclass="option">-mavx</span></samp> by default.
This option is only supported on i386 and x86-64 targets.
<br><dt><code>--enable-target-optspace</code><dd>Specify that target
libraries should be optimized for code space instead of code speed.
This is the default for the m32r platform.
<br><dt><code>--with-cpp-install-dir=</code><var>dirname</var><dd>Specify that the user visible <samp><spanclass="command">cpp</span></samp> program should be installed
in <samp><var>prefix</var><spanclass="file">/</span><var>dirname</var><spanclass="file">/cpp</span></samp>, in addition to <var>bindir</var>.
that runtime libraries should be installed in the compiler specific
subdirectory (<samp><var>libdir</var><spanclass="file">/gcc</span></samp>) rather than the usual places. In
addition, ‘<samp><spanclass="samp">libstdc++</span></samp>’'s include files will be installed into
<samp><var>libdir</var></samp> unless you overruled it by using
<samp><spanclass="option">--with-gxx-include-dir=</span><var>dirname</var></samp>. Using this option is
particularly useful if you intend to use several versions of GCC in
parallel. This is currently supported by ‘<samp><spanclass="samp">libgfortran</span></samp>’,
‘<samp><spanclass="samp">libjava</span></samp>’, ‘<samp><spanclass="samp">libmudflap</span></samp>’, ‘<samp><spanclass="samp">libstdc++</span></samp>’, and ‘<samp><spanclass="samp">libobjc</span></samp>’.
<br><dt><code>--enable-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that only a particular subset of compilers and
their runtime libraries should be built. For a list of valid values for
<var>langN</var> you can issue the following command in the
<samp><spanclass="file">gcc</span></samp> directory of your GCC source tree:<br>
<br><dt><code>--enable-stage1-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that a particular subset of compilers and their runtime
libraries should be built with the system C compiler during stage 1 of
the bootstrap process, rather than only in later stages with the
bootstrapped C compiler. The list of valid values is the same as for
<samp><spanclass="option">--enable-languages</span></samp>, and the option <code>all</code> will select all
of the languages enabled by <samp><spanclass="option">--enable-languages</span></samp>. This option is
primarily useful for GCC development; for instance, when a development
version of the compiler cannot bootstrap due to compiler bugs, or when
one is debugging front ends other than the C front end. When this
option is used, one can then build the target libraries for the
specified languages with the stage-1 compiler by using <samp><spanclass="command">make
stage1-bubble all-target</span></samp>, or run the testsuite on the stage-1 compiler
for the specified languages using <samp><spanclass="command">make stage1-start check-gcc</span></samp>.
<br><dt><code>--disable-libada</code><dd>Specify that the run-time libraries and tools used by GNAT should not
be built. This can be useful for debugging, or for compatibility with
previous Ada build procedures, when it was required to explicitly
do a ‘<samp><spanclass="samp">make -C gcc gnatlib_and_tools</span></samp>’.
<br><dt><code>--disable-libssp</code><dd>Specify that the run-time libraries for stack smashing protection
<p><var>key</var> defaults to GCC version number, and can be overridden by the
<samp><spanclass="option">--enable-win32-registry=</span><var>key</var></samp> option. Vendors and distributors
who use custom installers are encouraged to provide a different key,
perhaps one comprised of vendor name and GCC version number, to
avoid conflict with existing installations. This feature is enabled
by default, and can be disabled by <samp><spanclass="option">--disable-win32-registry</span></samp>
option. This option has no effect on the other hosts.
<br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit. This
option only applies to ‘<samp><spanclass="samp">m68k-sun-sunos</span><var>n</var></samp>’. On any other
system, <samp><spanclass="option">--nfp</span></samp> has no effect.
<br><dt><code>--enable-werror</code><dt><code>--disable-werror</code><dt><code>--enable-werror=yes</code><dt><code>--enable-werror=no</code><dd>When you specify this option, it controls whether certain files in the
compiler are built with <samp><spanclass="option">-Werror</span></samp> in bootstrap stage2 and later.
If you don't specify it, <samp><spanclass="option">-Werror</span></samp> is turned on for the main
development trunk. However it defaults to off for release branches and
final releases. The specific files which get <samp><spanclass="option">-Werror</span></samp> are
controlled by the Makefiles.
<br><dt><code>--enable-checking</code><dt><code>--enable-checking=</code><var>list</var><dd>When you specify this option, the compiler is built to perform internal
consistency checks of the requested complexity. This does not change the
generated code, but adds error checking within the compiler. This will
slow down the compiler and may only work properly if you are building
the compiler with GCC. This is ‘<samp><spanclass="samp">yes</span></samp>’ by default when building
over the checks may be had by specifying <var>list</var>. The categories of
checks available are ‘<samp><spanclass="samp">yes</span></samp>’ (most common checks
‘<samp><spanclass="samp">assert,misc,tree,gc,rtlflag,runtime</span></samp>’), ‘<samp><spanclass="samp">no</span></samp>’ (no checks at
all), ‘<samp><spanclass="samp">all</span></samp>’ (all but ‘<samp><spanclass="samp">valgrind</span></samp>’), ‘<samp><spanclass="samp">release</span></samp>’ (cheapest
checks ‘<samp><spanclass="samp">assert,runtime</span></samp>’) or ‘<samp><spanclass="samp">none</span></samp>’ (same as ‘<samp><spanclass="samp">no</span></samp>’).
Individual checks can be enabled with these flags ‘<samp><spanclass="samp">assert</span></samp>’,
‘<samp><spanclass="samp">rtlflag</span></samp>’, ‘<samp><spanclass="samp">runtime</span></samp>’, ‘<samp><spanclass="samp">tree</span></samp>’, and ‘<samp><spanclass="samp">valgrind</span></samp>’.
<p>The ‘<samp><spanclass="samp">valgrind</span></samp>’ check requires the external <samp><spanclass="command">valgrind</span></samp>
simulator, available from <ahref="http://valgrind.org/">http://valgrind.org/</a>. The
‘<samp><spanclass="samp">df</span></samp>’, ‘<samp><spanclass="samp">rtl</span></samp>’, ‘<samp><spanclass="samp">gcac</span></samp>’ and ‘<samp><spanclass="samp">valgrind</span></samp>’ checks are very expensive.
To disable all checking, ‘<samp><spanclass="samp">--disable-checking</span></samp>’ or
‘<samp><spanclass="samp">--enable-checking=none</span></samp>’ must be explicitly requested. Disabling
assertions will make the compiler and runtime slightly faster but
increase the risk of undetected internal errors causing wrong code to be
<br><dt><code>--disable-stage1-checking</code><dt><code>--enable-stage1-checking</code><dt><code>--enable-stage1-checking=</code><var>list</var><dd>If no <samp><spanclass="option">--enable-checking</span></samp> option is specified the stage1
<br><dt><code>--enable-coverage</code><dt><code>--enable-coverage=</code><var>level</var><dd>With this option, the compiler is built to collect self coverage
information, every time it is run. This is for internal development
purposes, and only works when the compiler is being built with gcc. The
<var>level</var> argument controls whether the compiler is built optimized or
not, values are ‘<samp><spanclass="samp">opt</span></samp>’ and ‘<samp><spanclass="samp">noopt</span></samp>’. For coverage analysis you
want to disable optimization, for performance analysis you want to
enable optimization. When coverage is enabled, the default level is
without optimization.
<br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory
allocation is gathered. This information is printed when using
<br><dt><code>--with-gc</code><dt><code>--with-gc=</code><var>choice</var><dd>With this option you can specify the garbage collector implementation
used during the compilation process. <var>choice</var> can be one of
‘<samp><spanclass="samp">page</span></samp>’ and ‘<samp><spanclass="samp">zone</span></samp>’, where ‘<samp><spanclass="samp">page</span></samp>’ is the default.
<br><dt><code>--enable-nls</code><dt><code>--disable-nls</code><dd>The <samp><spanclass="option">--enable-nls</span></samp> option enables Native Language Support (NLS),
which lets GCC output diagnostics in languages other than American
English. Native Language Support is enabled by default if not doing a
canadian cross build. The <samp><spanclass="option">--disable-nls</span></samp> option disables NLS.
<br><dt><code>--with-included-gettext</code><dd>If NLS is enabled, the <samp><spanclass="option">--with-included-gettext</span></samp> option causes the build
procedure to prefer its copy of GNU <samp><spanclass="command">gettext</span></samp>.
<br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the
inferior <code>catgets</code> interface, the GCC build procedure normally
ignores <code>catgets</code> and instead uses GCC's copy of the GNU
<code>gettext</code> library. The <samp><spanclass="option">--with-catgets</span></samp> option causes the
build procedure to use the host's <code>catgets</code> in this situation.
<br><dt><code>--with-libiconv-prefix=</code><var>dir</var><dd>Search for libiconv header files in <samp><var>dir</var><spanclass="file">/include</span></samp> and
libiconv library files in <samp><var>dir</var><spanclass="file">/lib</span></samp>.
<br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system. If you attempt to
configure GCC for a system (build, host, or target) which has been
obsoleted, and you do not specify this flag, configure will halt with an
error message.
<p>All support for systems which have been obsoleted in one release of GCC
is removed entirely in the next major release, unless someone steps
forward to maintain the port.
<br><dt><code>--enable-decimal-float</code><dt><code>--enable-decimal-float=yes</code><dt><code>--enable-decimal-float=no</code><dt><code>--enable-decimal-float=bid</code><dt><code>--enable-decimal-float=dpd</code><dt><code>--disable-decimal-float</code><dd>Enable (or disable) support for the C decimal floating point extension
that is in the IEEE 754-2008 standard. This is enabled by default only
on PowerPC, i386, and x86_64 GNU/Linux systems. Other systems may also
support it, but require the user to specifically enable it. You can
optionally control which decimal floating point format is used (either
‘<samp><spanclass="samp">bid</span></samp>’ or ‘<samp><spanclass="samp">dpd</span></samp>’). The ‘<samp><spanclass="samp">bid</span></samp>’ (binary integer decimal)
format is default on i386 and x86_64 systems, and the ‘<samp><spanclass="samp">dpd</span></samp>’
(densely packed decimal) format is default on PowerPC systems.
<br><dt><code>--with-gmp=</code><var>pathname</var><dt><code>--with-gmp-include=</code><var>pathname</var><dt><code>--with-gmp-lib=</code><var>pathname</var><dt><code>--with-mpfr=</code><var>pathname</var><dt><code>--with-mpfr-include=</code><var>pathname</var><dt><code>--with-mpfr-lib=</code><var>pathname</var><dt><code>--with-mpc=</code><var>pathname</var><dt><code>--with-mpc-include=</code><var>pathname</var><dt><code>--with-mpc-lib=</code><var>pathname</var><dd>If you do not have GMP (the GNU Multiple Precision library), the MPFR
library and/or the MPC library installed in a standard location and
you want to build GCC, you can explicitly specify the directory where
they are installed (‘<samp><spanclass="samp">--with-gmp=</span><var>gmpinstalldir</var></samp>’,
<br><dt><code>--with-ppl=</code><var>pathname</var><dt><code>--with-ppl-include=</code><var>pathname</var><dt><code>--with-ppl-lib=</code><var>pathname</var><dt><code>--with-cloog=</code><var>pathname</var><dt><code>--with-cloog-include=</code><var>pathname</var><dt><code>--with-cloog-lib=</code><var>pathname</var><dd>If you do not have PPL (the Parma Polyhedra Library) and the CLooG
libraries installed in a standard location and you want to build GCC,
you can explicitly specify the directory where they are installed
<br><dt><code>--with-host-libstdcxx=</code><var>linker-args</var><dd>If you are linking with a static copy of PPL, you can use this option
to specify how the linker should find the standard C++ library used
internally by PPL. Typical values of <var>linker-args</var> might be
‘<samp><spanclass="samp">-lstdc++</span></samp>’ or ‘<samp><spanclass="samp">-Wl,-Bstatic,-lstdc++,-Bdynamic -lm</span></samp>’. If you are
linking with a shared copy of PPL, you probably do not need this
option; shared library dependencies will cause the linker to search
<br><dt><code>--with-debug-prefix-map=</code><var>map</var><dd>Convert source directory names using <samp><spanclass="option">-fdebug-prefix-map</span></samp> when
building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated
list of maps of the form ‘<samp><var>old</var><spanclass="samp">=</span><var>new</var></samp>’.
<br><dt><code>--enable-linker-build-id</code><dd>Tells GCC to pass <samp><spanclass="option">--build-id</span></samp> option to the linker for all final
links (links performed without the <samp><spanclass="option">-r</span></samp> or <samp><spanclass="option">--relocatable</span></samp>
option), if the linker supports it. If you specify
<samp><spanclass="option">--enable-linker-build-id</span></samp>, but your linker does not
support <samp><spanclass="option">--build-id</span></samp> option, a warning is issued and the
<samp><spanclass="option">--enable-linker-build-id</span></samp> option is ignored. The default is off.
<br><dt><code>--enable-gnu-unique-object</code><dt><code>--disable-gnu-unique-object</code><dd>Tells GCC to use the gnu_unique_object relocation for C++ template
static data members and inline function local statics. Enabled by
default for a native toolchain with an assembler that accepts it and
<dt><code>--with-sysroot</code><dt><code>--with-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the root of a tree that contains
(a subset of) the root filesystem of the target operating system.
<br><dt><code>--with-build-sysroot</code><dt><code>--with-build-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the system root (see
<samp><spanclass="option">--with-sysroot</span></samp>) while building target libraries, instead of
the directory specified with <samp><spanclass="option">--with-sysroot</span></samp>. This option is
only useful when you are already using <samp><spanclass="option">--with-sysroot</span></samp>. You
can use <samp><spanclass="option">--with-build-sysroot</span></samp> when you are configuring with
<samp><spanclass="option">--prefix</span></samp> set to a directory that is different from the one in
which you are installing GCC and your target libraries.
<p>This option affects the system root for the compiler used to build
target libraries (which runs on the build system); it does not affect
the compiler which is used to build GCC itself.
<br><dt><code>--with-headers</code><dt><code>--with-headers=</code><var>dir</var><dd>Deprecated in favor of <samp><spanclass="option">--with-sysroot</span></samp>.
Specifies that target headers are available when building a cross compiler.
The <var>dir</var> argument specifies a directory which has the target include
files. These include files will be copied into the <samp><spanclass="file">gcc</span></samp> install
directory. <em>This option with the </em><var>dir</var><em> argument is required</em> when
building a cross compiler, if <samp><var>prefix</var><spanclass="file">/</span><var>target</var><spanclass="file">/sys-include</span></samp>
doesn't pre-exist. If <samp><var>prefix</var><spanclass="file">/</span><var>target</var><spanclass="file">/sys-include</span></samp> does
pre-exist, the <var>dir</var> argument may be omitted. <samp><spanclass="command">fixincludes</span></samp>
will be run on these files to make them compatible with GCC.
<br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross
compiler. When crossing to GNU/Linux, you need the headers so GCC
<br><dt><code>--with-libs</code><dt><code>--with-libs="</code><var>dir1</var><var>dir2</var><code> ... </code><var>dirN</var><code>"</code><dd>Deprecated in favor of <samp><spanclass="option">--with-sysroot</span></samp>.
<p>The following option applies to the build of the Java front end.
<dl>
<dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries
used by GCJ should not be built. This is useful in case you intend
to use GCJ with some other run-time, or you're going to install it
separately, or it just happens not to build on your particular
machine. In general, if the Java front end is enabled, the GCJ
libraries will be enabled too, unless they're known to not work on
the target platform. If GCJ is enabled but ‘<samp><spanclass="samp">libgcj</span></samp>’ isn't built, you
may need to port it; in this case, before modifying the top-level
<samp><spanclass="file">configure.in</span></samp> so that ‘<samp><spanclass="samp">libgcj</span></samp>’ is enabled by default on this platform,
you may use <samp><spanclass="option">--enable-libgcj</span></samp> to override the default.
</dl>
<p>The following options apply to building ‘<samp><spanclass="samp">libgcj</span></samp>’.
<dt><code>--enable-java-maintainer-mode</code><dd>By default the ‘<samp><spanclass="samp">libjava</span></samp>’ build will not attempt to compile the
<samp><spanclass="file">.java</span></samp> source files to <samp><spanclass="file">.class</span></samp>. Instead, it will use the
<samp><spanclass="file">.class</span></samp> files from the source tree. If you use this option you
must have executables named <samp><spanclass="command">ecj1</span></samp> and <samp><spanclass="command">gjavah</span></samp> in your path
for use by the build. You must use this option if you intend to
modify any <samp><spanclass="file">.java</span></samp> files in <samp><spanclass="file">libjava</span></samp>.
<br><dt><code>--with-java-home=</code><var>dirname</var><dd>This ‘<samp><spanclass="samp">libjava</span></samp>’ option overrides the default value of the
‘<samp><spanclass="samp">java.home</span></samp>’ system property. It is also used to set
‘<samp><spanclass="samp">sun.boot.class.path</span></samp>’ to <samp><var>dirname</var><spanclass="file">/lib/rt.jar</span></samp>. By
default ‘<samp><spanclass="samp">java.home</span></samp>’ is set to <samp><var>prefix</var></samp> and
‘<samp><spanclass="samp">sun.boot.class.path</span></samp>’ to
<br><dt><code>--enable-reduced-reflection</code><dd>Build most of libgcj with <samp><spanclass="option">-freduced-reflection</span></samp>. This reduces
the size of libgcj at the expense of not being able to do accurate
reflection on the classes it contains. This option is safe if you
know that code using libgcj will never use reflection on the standard
runtime classes in libgcj (including using serialization, RMI or CORBA).
<br><dt><code>--without-libffi</code><dd>Don't use ‘<samp><spanclass="samp">libffi</span></samp>’. This will disable the interpreter and JNI
support as well, as these require ‘<samp><spanclass="samp">libffi</span></samp>’ to work.
<br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <samp><spanclass="file">.java</span></samp> source files to be
compiled into <samp><spanclass="file">.class</span></samp> files in one invocation of
‘<samp><spanclass="samp">gcj</span></samp>’. This can speed up build time, but is more
resource-intensive. If this option is unspecified or
disabled, ‘<samp><spanclass="samp">gcj</span></samp>’ is invoked once for each <samp><spanclass="file">.java</span></samp>
file to compile into a <samp><spanclass="file">.class</span></samp> file.
<br><dt><code>--with-libiconv-prefix=DIR</code><dd>Search for libiconv in <samp><spanclass="file">DIR/include</span></samp> and <samp><spanclass="file">DIR/lib</span></samp>.
<br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions.
‘<samp><spanclass="samp">configure</span></samp>’ ordinarily picks the correct value based on the platform.
Only use this option if you are sure you need a different setting.
<br><dt><code>--with-system-zlib</code><dd>Use installed ‘<samp><spanclass="samp">zlib</span></samp>’ rather than that included with GCC.
<br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW ‘<samp><spanclass="samp">libgcj</span></samp>’ translates between UNICODE
<br><dt><code>--enable-java-home</code><dd>If enabled, this creates a JPackage compatible SDK environment during install.
Note that if –enable-java-home is used, –with-arch-directory=ARCH must also
be specified.
<br><dt><code>--with-arch-directory=ARCH</code><dd>Specifies the name to use for the <samp><spanclass="file">jre/lib/ARCH</span></samp> directory in the SDK
environment created when –enable-java-home is passed. Typical names for this
directory include i386, amd64, ia64, etc.
<br><dt><code>--with-os-directory=DIR</code><dd>Specifies the OS directory for the SDK include directory. This is set to auto
detect, and is typically 'linux'.
<br><dt><code>--with-origin-name=NAME</code><dd>Specifies the JPackage origin name. This defaults to the 'gcj' in
java-1.5.0-gcj.
<br><dt><code>--with-arch-suffix=SUFFIX</code><dd>Specifies the suffix for the sdk directory. Defaults to the empty string.
Examples include '.x86_64' in 'java-1.5.0-gcj-1.5.0.0.x86_64'.
<br><dt><code>--with-jvm-root-dir=DIR</code><dd>Specifies where to install the SDK. Default is $(prefix)/lib/jvm.
<br><dt><code>--with-jvm-jar-dir=DIR</code><dd>Specifies where to install jars. Default is $(prefix)/lib/jvm-exports.
<br><dt><code>--with-python-dir=DIR</code><dd>Specifies where to install the Python modules used for aot-compile. DIR should
not include the prefix used in installation. For example, if the Python modules
are to be installed in /usr/lib/python2.5/site-packages, then
–with-python-dir=/lib/python2.5/site-packages should be passed. If this is
not specified, then the Python modules are installed in $(prefix)/share/python.
<br><dt><code>--enable-aot-compile-rpm</code><dd>Adds aot-compile-rpm to the list of installed scripts.
<dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively,
translating to and from UNICODE when using these functions. If
unspecified, this is the default.
<br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Adds
<code>-lunicows</code> to <samp><spanclass="file">libgcj.spec</span></samp> to link with ‘<samp><spanclass="samp">libunicows</span></samp>’.
<samp><spanclass="file">unicows.dll</span></samp> needs to be deployed on Microsoft Windows 9X machines
running built executables. <samp><spanclass="file">libunicows.a</span></samp>, an open-source
import library around Microsoft's <code>unicows.dll</code>, is obtained from
<ahref="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details
on getting <samp><spanclass="file">unicows.dll</span></samp> from Microsoft.
<br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Does <em>not</em>
add <code>-lunicows</code> to <samp><spanclass="file">libgcj.spec</span></samp>. The built executables will
<h5class="subsubheading"><aname="TOC7"></a>Overriding <samp><spanclass="command">configure</span></samp> test results</h5>
<p>Sometimes, it might be necessary to override the result of some
<samp><spanclass="command">configure</span></samp> test, for example in order to ease porting to a new
system or work around a bug in a test. The toplevel <samp><spanclass="command">configure</span></samp>
script provides three variables for this:
<dl>
<dt><code>build_configargs</code><dd><aname="index-g_t_0040code_007bbuild_005fconfigargs_007d-3"></a>The contents of this variable is passed to all build <samp><spanclass="command">configure</span></samp>
scripts.
<br><dt><code>host_configargs</code><dd><aname="index-g_t_0040code_007bhost_005fconfigargs_007d-4"></a>The contents of this variable is passed to all host <samp><spanclass="command">configure</span></samp>
scripts.
<br><dt><code>target_configargs</code><dd><aname="index-g_t_0040code_007btarget_005fconfigargs_007d-5"></a>The contents of this variable is passed to all target <samp><spanclass="command">configure</span></samp>
scripts.
</dl>
<p>In order to avoid shell and <samp><spanclass="command">make</span></samp> quoting issues for complex
overrides, you can pass a setting for <samp><spanclass="env">CONFIG_SITE</span></samp> and set
