gdb: Add almost-working recipe and patchset for 8.1 (!!!).

Reworking the Haiku backend from 6.3 (2004) to 8.1 (2018) surprisingly
only took a few hours to get it to compile ... but then it crashes when
attempting to start inferiors with a use-after free that I spent over
three hours debugging and got nowhere.

It seems that somehow, an event object that is created, deleted, and otherwise
managed entirely by the Haiku patches is somehow deleted between waits?!
The guarded heap was of not much help here, it obviously caught the UAF
before the regular heap did, but couldn't even say where it had been freed,
only where it had been allocated; and the allocation location looked
completely wrong also. So, this is very close, but it doesn't work just yet.

It would sure be nice to have Qt Creator's GDB support (which needs
Python-enabled GDB) working...

dev-util/gdb/gdb-8.1.recipe

@@ -0,0 +1,102 @@
+SUMMARY="The GNU debugger"
+DESCRIPTION="GDB is the GNU debugger. It allows you to see what is going on \
+'inside' another program while it executes -- or what another program was \
+doing at the moment it crashed.
+
+GDB can do four main kinds of things (plus other things in support of \
+these) to help you catch bugs in the act:
+
+ * Start your program, specifying anything that might affect its behavior.
+ * Make your program stop on specified conditions.
+ * Examine what has happened, when your program has stopped.
+ * Change things in your program, so you can experiment with correcting \
+the effects of one bug and go on to learn about another.
+
+The program being debugged can be written in Ada, C, C++, Objective-C, \
+Pascal (and many other languages). Those programs might be executing \
+on the same machine as GDB (native) or on another machine (remote). \
+GDB can run on most popular UNIX and Microsoft Windows variants."
+HOMEPAGE="https://sourceware.org/gdb/"
+COPYRIGHT="2018 Free Software Foundation, Inc."
+LICENSE="GNU GPL v2
+	GNU GPL v3"
+REVISION="1"
+SOURCE_URI="https://ftp.gnu.org/gnu/gdb/gdb-$portVersion.tar.xz"
+CHECKSUM_SHA256="af61a0263858e69c5dce51eab26662ff3d2ad9aa68da9583e8143b5426be4b34"
+PATCHES="gdb-$portVersion.patch"
+
+ARCHITECTURES="!x86_gcc2 ?x86 ?x86_64"
+
+PROVIDES="
+	gdb = $portVersion
+	cmd:gdb = $portVersion
+	devel:libbfd = $portVersion
+	devel:libopcodes = $portVersion
+	"
+REQUIRES="
+	haiku
+	lib:libz
+	lib:libiconv
+	lib:libncurses
+	lib:libpython2.7
+	lib:libexpat
+	"
+
+BUILD_REQUIRES="
+	devel:libz
+	devel:libiconv
+	devel:libncurses
+	devel:libpython2.7
+	devel:libexpat
+	"
+BUILD_PREREQUIRES="
+	haiku_devel
+	cmd:awk
+	cmd:cmp
+	cmd:bison
+	cmd:flex
+	cmd:gcc
+	cmd:ld
+	cmd:m4
+	cmd:make
+	cmd:makeinfo
+	cmd:yacc
+	cmd:python
+	"
+
+TEST_REQUIRES="
+	cmd:runtest
+	"
+
+BUILD()
+{
+	if [ $targetArchitecture = x86 ]; then
+    	TARGET=i586-pc-haiku
+	elif [ $targetArchitecture = x86_64 ]; then
+		TARGET=x86_64-unknown-haiku
+	fi
+
+	runConfigure --omit-dirs "docDir dataRootDir" ./configure \
+		--host=$TARGET --target=$TARGET \
+		--disable-nls --with-system-zlib
+
+	make configure-host
+	make configure-target
+
+	make $jobArgs
+}
+
+INSTALL()
+{
+	make install
+
+	prepareInstalledDevelLibs \
+		libbfd \
+		libopcodes
+	rm $developLibDir/*.la
+}
+
+TEST()
+{
+	make check
+}