Add support for CFLAGS-OMIT-file from nptl

Makerules

@@ -92,11 +92,10 @@ disp_t_strip   = $($(DISP)_disp_t_strip)
 disp_ar        = $($(DISP)_disp_ar)
 disp_ld        = $($(DISP)_disp_ld)
 
-cmd_compile.c = $(CC) -c $< -o $@ $(CFLAGS) $(ARCH_CFLAGS) $(CFLAGS-$(suffix $@)) $(CFLAGS-$(notdir $(^D))) $(CFLAGS-$(subst $(top_srcdir),,$(dir $<))) $(CFLAGS-$(notdir $<)) $(CFLAGS-$(notdir $@))
+cmd_compile.c = $(CC) -c $< -o $@ $(CFLAGS) $(ARCH_CFLAGS) $(CFLAGS-$(suffix $@)) $(filter-out $(CFLAGS-OMIT-$(notdir $<)),$(CFLAGS-$(notdir $(^D)))) $(CFLAGS-$(subst $(top_srcdir),,$(dir $<))) $(CFLAGS-$(notdir $<)) $(CFLAGS-$(notdir $@))
 cmd_compile.S = $(cmd_compile.c) $(ASFLAGS) $(ARCH_ASFLAGS) $(ASFLAGS-$(suffix $@)) $(ASFLAGS-$(notdir $<)) $(ASFLAGS-$(notdir $@))
 cmd_compile.m = $(cmd_compile.c) -DL_$(patsubst %$(suffix $(notdir $@)),%,$(notdir $@))
 cmd_compile-m = $(CC) $^ -c -o $@ $(CFLAGS) $(ARCH_CFLAGS) $(CFLAGS-$(suffix $@)) $(CFLAGS-$(notdir $(@D))) $(CFLAGS-$(notdir $@))
-#cmd_compile-m = $(CC) $^ -c -o $@ $(CFLAGS) $(ARCH_CFLAGS) $(CFLAGS-$(suffix $@)) $(CFLAGS-$(notdir $(@D))) $(CFLAGS-$(notdir $@)) $(CFLAGS-multi-y)
 cmd_strip     = $(STRIPTOOL) $(STRIP_FLAGS) $^
 cmd_t_strip   = $(STRIPTOOL) $(STRIP_FLAGS) $@
 cmd_ar        = $(AR) $(ARFLAGS) $@ $^