configure: allow building GDB along with the buildtools

from a stock GDB source tree.

I was getting tired of doing it manually.

Note the prefix is not exactly the same as the buildtools since the
machine triplet is different, but it's not an issue.

Tested with arm and ppc with GDB 7.8. Might need patching gdbTarget for other archs,
as stock GDB doesn't know about Haiku.

build/scripts/build_cross_tools_gcc4

@@ -15,15 +15,18 @@ buildToolsDir=$3
 installDir=$4
 shift 4
 additionalMakeArgs=$*
+gdbSourceDir="$HAIKU_USE_GDB"
 
 ccFlags="-O2"
 cxxFlags="-O2"
 binutilsTargets="$haikuMachine"
+gdbTarget="$haikuMachine"
 case $haikuMachine in
 i586-*)
 	binutilsConfigureArgs="--disable-multilib"
 	gccConfigureArgs="--disable-multilib"
 	binutilsTargets="$binutilsTargets,i386-efi-pe,x86_64-efi-pe"
+	gdbConfigureArgs="--disable-multilib"
 	;;
 x86_64-*)
 	# GCC's default is to enable multilib, but there is a bug when
@@ -31,10 +34,12 @@ x86_64-*)
 	# failure
 	binutilsConfigureArgs=""
 	binutilsTargets="$binutilsTargets,i386-efi-pe,x86_64-efi-pe"
+	gdbConfigureArgs="--disable-multilib"
 	;;
 m68k-*)
 	binutilsConfigureArgs="--enable-multilib"
 	gccConfigureArgs="--enable-multilib"
+	gdbConfigureArgs="--disable-multilib"
 	;;
 arm-*)
 	# Multilib creates a lot of confusion as the wrong libs end up being linked.
@@ -47,15 +52,20 @@ arm-*)
 	# TODO: Disable building with TLS support for ARM until implemented.
 	binutilsConfigureArgs="$binutilsConfigureArgs --disable-tls"
 	gccConfigureArgs="$gccConfigureArgs --disable-tls"
+	gdbConfigureArgs="--disable-multilib --disable-werror -enable-interwork"
+	gdbTarget="arm-unknown-elf"
 	;;
 powerpc-*)
 	binutilsConfigureArgs="--disable-multilib"
 	gccConfigureArgs="--disable-multilib"
 	binutilsTargets="$binutilsTargets,powerpc-apple-linux,powerpc-apple-freebsd,powerpc-apple-vxworks"
+	gdbConfigureArgs="--disable-multilib --disable-werror"
+	gdbTarget="powerpc-unknown-elf"
 	;;
 *)
 	binutilsConfigureArgs="--disable-multilib"
 	gccConfigureArgs="--disable-multilib"
+	gdbConfigureArgs="--disable-multilib"
 	;;
 esac
 
@@ -75,6 +85,11 @@ if [ ! -d "$buildToolsDir" ]; then
 	exit 1
 fi
 
+if [ -n "$gdbSourceDir" -a ! -d "$gdbSourceDir" ]; then
+	echo "No such directory: \"$gdbSourceDir\"" >&2
+	exit 1
+fi
+
 
 # create the output dir
 mkdir -p "$installDir" || exit 1
@@ -95,6 +110,12 @@ cd "$installDir"
 installDir=$(pwd)
 cd "$currentDir"
 
+if [ -n "$gdbSourceDir" ]; then
+cd "$gdbSourceDir"
+gdbSourceDir=$(pwd)
+cd "$currentDir"
+fi
+
 binutilsSourceDir="$buildToolsDir/binutils"
 gccSourceDir="$buildToolsDir/gcc"
 
@@ -117,6 +138,7 @@ find "$binutilsSourceDir" "$gccSourceDir" -name \*.info -print0 | xargs -0 touch
 objDir="${installDir}-build"
 binutilsObjDir="$objDir/binutils"
 gccObjDir="$objDir/gcc"
+gdbObjDir="$objDir/gdb"
 stdcxxObjDir="$objDir/stdcxx"
 sysrootDir="$installDir/sysroot"
 tmpIncludeDir="$sysrootDir/boot/system/develop/headers"
@@ -124,8 +146,8 @@ tmpLibDir="$sysrootDir/boot/system/develop/lib"
 
 rm -rf "$installDir" "$objDir"
 
-mkdir -p "$installDir" "$objDir" "$binutilsObjDir" "$gccObjDir" "$stdcxxObjDir" \
-	"$tmpIncludeDir" "$tmpLibDir" || exit 1
+mkdir -p "$installDir" "$objDir" "$binutilsObjDir" "$gccObjDir" "$gdbObjDir" \
+	"$stdcxxObjDir" "$tmpIncludeDir" "$tmpLibDir" || exit 1
 mkdir -p "$installDir/lib/gcc/$haikuMachine/$gccVersion"
 
 if [ "$HAIKU_USE_GCC_GRAPHITE" = 1 ]; then
@@ -155,6 +177,17 @@ fi
 # force the POSIX locale, as the build (makeinfo) might choke otherwise
 export LC_ALL=POSIX
 
+# build gdb
+if [ -n "$HAIKU_USE_GDB" ]; then
+cd "$gdbObjDir"
+	"$gdbSourceDir/configure" \
+		--prefix="$installDir" --target=$gdbTarget \
+		$gdbConfigureArgs \
+		|| exit 1
+	$MAKE $additionalMakeArgs || exit 1
+	$MAKE $additionalMakeArgs install || exit 1
+fi
+
 # build binutils
 cd "$binutilsObjDir"
 CFLAGS="$ccFlags" CXXFLAGS="$cxxFlags" "$binutilsSourceDir/configure" \