kernel-devsrc: Handle ppc crtsaves.o explictly for now

Resolve kernel module build failures for qemuppc by including crtsaves.o.

I'm not particularly happy to be doing this, it should perhaps be contained
in the kernel-dev package. Until the overlap between kernel-devsrc and
kernel-dev is resolved, this at least removed the regressions.

(From OE-Core rev: 5fa888894384eff18df77d0a5aaa007eba1406c8)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-kernel/linux/kernel-devsrc.bb

@@ -46,6 +46,14 @@ do_install() {
         cd ${S}
         find . -type d -name '.git*' -prune -o -type f -print0 | cpio --null -pdlu $kerneldir
         oe_runmake -C $kerneldir CC="${KERNEL_CC}" LD="${KERNEL_LD}" clean _mrproper_scripts
+
+        # As of Linux kernel version 3.0.1, the clean target removes
+        # arch/powerpc/lib/crtsavres.o which is present in
+        # KBUILD_LDFLAGS_MODULE, making it required to build external modules.
+        if [ ${ARCH} = "powerpc" ]; then
+                mkdir -p $kerneldir/arch/powerpc/lib/
+                cp ${S}/arch/powerpc/lib/crtsavres.o $kerneldir/arch/powerpc/lib/crtsavres.o
+        fi
 }
 
 PACKAGES = "kernel-devsrc"