patch: bump to 2.7.6, switch to tar.xz, add gcc2 patch. (#3200)

The 2nd patch in patch-2.7.6-gcc2.patchset is almost identical to
the 2nd one in tar-1.30-gcc2.patchset, and the files they patch:

*    tar-1.30/gnu/backupfile.c *    tar-1.30/gnu/parse-datetime.y
* patch-2.7.6/lib/backupfile.c * patch-2.7.6/lib/parse-datetime.y

are identical before and after the patch. There is only one diff,
in line 3: we have a "2017" for tar and a "2018" for patch.

sys-devel/patch/patch-2.7.6.recipe

@@ -0,0 +1,66 @@
+SUMMARY="Utility to apply diffs to files"
+DESCRIPTION="Patch takes a patch file containing a difference listing produced \
+by the diff program and applies those differences to one or more original \
+files, producing patched versions."
+HOMEPAGE="https://savannah.gnu.org/projects/patch/"
+COPYRIGHT="2012-2018 Free Software Foundation, Inc."
+LICENSE="GNU GPL v3"
+REVISION="1"
+SOURCE_URI="https://ftpmirror.gnu.org/patch/patch-$portVersion.tar.xz
+	https://ftp.gnu.org/gnu/patch/patch-$portVersion.tar.xz"
+CHECKSUM_SHA256="ac610bda97abe0d9f6b7c963255a11dcb196c25e337c61f94e4778d632f1d8fd"
+PATCHES="patch-$portVersion.patchset"
+if [ "$effectiveTargetArchitecture" = x86_gcc2 ]; then
+PATCHES+="
+	patch-$portVersion-gcc2.patchset
+	"
+fi
+
+ARCHITECTURES="x86_gcc2 x86 x86_64 arm"
+if [ "$targetArchitecture" = x86_gcc2 ]; then
+SECONDARY_ARCHITECTURES="x86"
+fi
+
+PROVIDES="
+	patch$secondaryArchSuffix = $portVersion
+	cmd:patch = $portVersion
+	"
+REQUIRES="
+	haiku$secondaryArchSuffix
+	"
+if [ -n "$secondaryArchSuffix" ]; then
+CONFLICTS="
+	patch
+	"
+fi
+
+BUILD_REQUIRES="
+	haiku${secondaryArchSuffix}_devel
+	"
+BUILD_PREREQUIRES="
+	cmd:awk
+	cmd:gcc$secondaryArchSuffix
+	cmd:make
+	"
+
+TEST_REQUIRES="
+	cmd:diff
+	cmd:git
+	"
+
+BUILD()
+{
+	runConfigure --omit-dirs binDir ./configure --bindir="$prefix"/bin
+	make
+}
+
+INSTALL()
+{
+	make install
+	rm "$libDir"/charset.alias
+}
+
+TEST()
+{
+	make check
+}