[PATCH] uml: cleanup unprofile expression and build infrastructure

*) Rather than duplicate in various buggy ways the application of
   CFLAGS_NO_HARDENING and UNPROFILE (which apply to the same files),
   centralize it in Makefile.rules.  UNPROFILE_OBJS mustn't be listed in
   USER_OBJS but are compiled as such.

I've also verified that unprofile didn't work in the current form, because we
set _c_flags directly (using CFLAGS and not USER_CFLAGS, which is wrong),
which is normally used by c_flags, but we also override c_flags for all
USER_OBJS, and there we don't call unprofile.

Instead it only worked for unmap.o, the only one which wasn't a USER_OBJ.

We need to set c_flags (which is not a public Kbuild API) to clear a lot of
compilation flags like -nostdinc which Kbuild forces on everything.

*) Rather than $(CFLAGS_$(notdir $@)), which expands to CFLAGS_anObj.s when
   building "anObj.s", use $(CFLAGS_$(*F).o) which always accesses
   CFLAGS_anObj.o, like done by Kbuild.

*) Make c_flags apply to all targets having the same basename, rather than
   listing .s, .i, .lst and .o, with the use (which I tested) of

	$(USER_OBJS:.o=.%): c_flags = ...

and of

 -      $(obj)/unmap.c: _c_flags = ...
 +      $(obj)/unmap.%: _c_flags = ...

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/sys-i386/Makefile

@@ -8,16 +8,16 @@ subarch-obj-y = lib/bitops.o kernel/semaphore.o
 subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem.o
 subarch-obj-$(CONFIG_MODULES) += kernel/module.o
 
-USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o stub_segv.o
+USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o
 
 USER_OBJS += user-offsets.s
 extra-y += user-offsets.s
 
-CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)
-
 extra-$(CONFIG_MODE_TT) += unmap.o
 
+UNPROFILE_OBJS := stub_segv.o
+CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)
+
 include arch/um/scripts/Makefile.rules
 
-$(obj)/stub_segv.o $(obj)/unmap.o: \
-	_c_flags = $(call unprofile,$(CFLAGS))
+$(obj)/unmap.%: _c_flags = $(call unprofile,$(CFLAGS))