Build a separate libsupc++ for the kernel with correct flags.

Kernel mode code on x86_64 needs to be built with -mno-red-zone as
interrupts would corrupt the red zone if it were in use. However, the
kernel is linked with libsupc++, which was not compiled with
-mno-red-zone. If an interrupt occurred in libsupc++ code the red zone
would get corrupted. This was causing random panics, particularly under
heavy system load. Therefore, on x86_64 a separate build of libsupc++
with -mno-red-zone is now done for the kernel to use. Note: this commit
will require a rerun of configure and rebuild of cross tools.

build/scripts/build_cross_tools_gcc4

@@ -33,6 +33,7 @@ x86_64-*)
 	# failure
 	binutilsConfigureArgs=""
 	gccConfigureArgs=""
+	kernelSupcxxFlags="-mno-red-zone"
 	;;
 m68k-*)
 	binutilsConfigureArgs="--enable-multilib"
@@ -45,6 +46,7 @@ arm-*)
 *)
 	binutilsConfigureArgs="--disable-multilib"
 	gccConfigureArgs="--disable-multilib"
+	kernelSupcxxFlags=
 	;;
 esac
 
@@ -101,13 +103,14 @@ installDir=$haikuOutputDir/cross-tools
 objDir=$haikuOutputDir/cross-tools-build
 binutilsObjDir=$objDir/binutils
 gccObjDir=$objDir/gcc
+stdcxxObjDir=$objDir/stdcxx
 tmpIncludeDir=$objDir/sysincludes
 tmpLibDir=$objDir/syslibs
 
 rm -rf $installDir $objDir
 
-mkdir -p $installDir $objDir $binutilsObjDir $gccObjDir $tmpIncludeDir \
-	$tmpLibDir || exit 1
+mkdir -p $installDir $objDir $binutilsObjDir $gccObjDir $stdcxxObjDir \
+	$tmpIncludeDir $tmpLibDir || exit 1
 mkdir -p $installDir/lib/gcc/$haikuMachine/$gccVersion
 
 
@@ -163,6 +166,20 @@ $MAKE $additionalMakeArgs install || {
 	exit 1
 }
 
+# build libsupc++ for the kernel if the target arch requires it
+if [ -n "$kernelSupcxxFlags" ]; then
+	cd $stdcxxObjDir
+	CFLAGS="-O2 $kernelSupcxxFlags" CXXFLAGS="-O2 $kernelSupcxxFlags" \
+		$gccSourceDir/libstdc++-v3/configure --prefix=$installDir \
+		--target=$haikuMachine --host=$haikuMachine --disable-shared \
+		--disable-multilib || exit 1
+	$MAKE $additionalMakeArgs -C libsupc++ || {
+		echo "Error: Building kernel libsupc++ failed." >&2
+		exit 1
+	}
+	cp libsupc++/.libs/libsupc++.a $installDir/$haikuMachine/lib/libsupc++-kernel.a
+fi
+
 # cleanup
 
 # remove the system headers from the installation dir