gcc: update to 4.6.3. Build multilib pkgs on x86_64.

srcpkgs/gcc/libgomp32.template

@@ -0,0 +1,16 @@
+# Template file for 'libgomp32'.
+#
+short_desc="GCC OpenMP v3.0 shared support library (32bit)"
+long_desc="${long_desc}
+
+ This package contains the 32bit GCC shared support library which is needed
+ for OpenMP v3.0 support."
+
+noverifyrdeps=yes
+
+Add_dependency run libgcc32
+Add_dependency run glibc32
+
+do_install() {
+	vmove "usr/lib32/libgomp.*" usr/lib32
+}