main/gcc: expand cross-compiler lib symlinks as linker scripts

This makes gcc to search the actual library from libpath. Needed
because cross-compiler's library is really in --sysroot path.
Alternative is to move the .so files to separate new target arch
specific gcc-dev package. But that'd require musl-dev or build-base
to depend on it, so this is the easy fix around it.

main/gcc/APKBUILD

@@ -382,6 +382,16 @@ package() {
 		rm -rf "$pkgdir"/usr/bin/cc "$pkgdir"/usr/include "$pkgdir"/usr/share
 		# libcc1 does not depend on target, don't ship it
 		rm -rf "$pkgdir"/usr/lib/libcc1.so*
+
+		# fixup gcc library symlinks to be linker scripts so
+		# linker finds the libs from relocated sysroot
+		for so in "$pkgdir"/usr/$CTARGET/lib/*.so; do
+			if [ -h "$so" ]; then
+				local _real=$(basename $(readlink "$so"))
+				rm -f "$so"
+				echo "GROUP ($_real)" > "$so"
+			fi
+		done
 	fi
 }