Fix linking modules against crtsavres.o

Previously we got
  CC      drivers/char/hw_random/rng-core.mod.o
  LD [M]  drivers/char/hw_random/rng-core.ko
/there/src/buildroot.git.ppc/build_powerpc_nofpu/staging_dir/usr/bin/powerpc-linux-uclibc-ld: arch/powerpc/lib/crtsavres.o: No such file: No such file or directory

	* Makefile (LDFLAGS_MODULE_PREREQ): New variable to hold prerequisite
	files for modules.
	* arch/powerpc/Makefile: add crtsavres.o to LDFLAGS_MODULE_PREREQ.
	* scripts/Makefile.modpost (cmd_as_o_S): Copy from Makefile.build.
	(cmd_ld_ko_o): Also link LDFLAGS_MODULE_PREREQ.
	Provide rule to build objects from assembler.

Signed-off-by:  Bernhard Reutner-Fischer  <rep.dot.nop@gmail.com>

diff -rup ../../x/linux-2.6.26.5.old/arch/powerpc/Makefile linux-2.6.26.5/arch/powerpc/Makefile
--- ../../x/linux-2.6.26.5.old/arch/powerpc/Makefile	2008-09-08 19:40:20.000000000 +0200
+++ linux-2.6.26.5/arch/powerpc/Makefile	2008-10-07 14:28:08.000000000 +0200
@@ -97,7 +97,7 @@ else
 	KBUILD_CFLAGS += $(call cc-option,-mtune=power4)
 endif
 else
-LDFLAGS_MODULE	+= arch/powerpc/lib/crtsavres.o
+LDFLAGS_MODULE_PREREQ += arch/powerpc/lib/crtsavres.o
 endif
 
 ifeq ($(CONFIG_TUNE_CELL),y)
diff -rup ../../x/linux-2.6.26.5.old/Makefile linux-2.6.26.5/Makefile
--- ../../x/linux-2.6.26.5.old/Makefile	2008-09-08 19:40:20.000000000 +0200
+++ linux-2.6.26.5/Makefile	2008-10-07 14:15:59.000000000 +0200
@@ -318,6 +318,7 @@ MODFLAGS	= -DMODULE
 CFLAGS_MODULE   = $(MODFLAGS)
 AFLAGS_MODULE   = $(MODFLAGS)
 LDFLAGS_MODULE  =
+LDFLAGS_MODULE_PREREQ  =
 CFLAGS_KERNEL	=
 AFLAGS_KERNEL	=
 
@@ -342,7 +343,7 @@ KERNELVERSION = $(VERSION).$(PATCHLEVEL)
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
-export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
+export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE LDFLAGS_MODULE_PREREQ CHECK CHECKFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
diff -rup ../../x/linux-2.6.26.5.old/scripts/Makefile.modpost linux-2.6.26.5/scripts/Makefile.modpost
--- ../../x/linux-2.6.26.5.old/scripts/Makefile.modpost	2008-09-08 19:40:20.000000000 +0200
+++ linux-2.6.26.5/scripts/Makefile.modpost	2008-10-07 14:24:34.000000000 +0200
@@ -122,14 +122,21 @@ quiet_cmd_cc_o_c = CC      $@
       cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)	\
 		   -c -o $@ $<
 
-$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
+quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
+cmd_as_o_S       = $(CC) $(a_flags) $(AFLAGS_MODULE) -c -o $@ $<
+
+$(LDFLAGS_MODULE_PREREQ): %.o: %.S FORCE
+	$(call if_changed_dep,as_o_S)
+
+$(modules:.ko=.mod.o): %.mod.o: %.mod.c $(LDFLAGS_MODULE_PREREQ) FORCE
 	$(call if_changed_dep,cc_o_c)
 
 targets += $(modules:.ko=.mod.o)
 
 # Step 6), final link of the modules
 quiet_cmd_ld_ko_o = LD [M]  $@
-      cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@		\
+      cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE_PREREQ)	\
+			  $(LDFLAGS_MODULE) -o $@		\
 			  $(filter-out FORCE,$^)
 
 $(modules): %.ko :%.o %.mod.o FORCE