kbuild: Add cc-option-align

gcc version >= 3.00 shifted from -malign-* to -falign-*. $(cc-option-align) will
based on current gcc version specify the right prefix for the align option.
Documented in Documentation/makefiles.txt
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Documentation/kbuild/makefiles.txt

@@ -997,6 +997,21 @@ When kbuild executes the following steps are followed (roughly):
 	option. When $(biarch) equals to y the expanded variables $(aflags-y)
 	and $(cflags-y) will be assigned the values -a32 and -m32.
 
+    cc-option-align
+	gcc version >= 3.0 shifted type of options used to speify
+	alignment of functions, loops etc. $(cc-option-align) whrn used
+	as prefix to the align options will select the right prefix:
+	gcc < 3.00
+		cc-option-align = -malign
+	gcc >= 3.00
+		cc-option-align = -falign
+	
+	Example:
+		CFLAGS += $(cc-option-align)-functions=4
+
+	In the above example the option -falign-functions=4 is used for
+	gcc >= 3.00. For gcc < 3.00 -malign-functions=4 is used.
+	
     cc-version
 	cc-version return a numerical version of the $(CC) compiler version.
 	The format is <major><minor> where both are two digits. So for example

Makefile

@@ -295,6 +295,11 @@ check_gcc = $(warning check_gcc is deprecated - use cc-option) \
 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
                 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
 
+# cc-option-align
+# Prefix align with either -falign or -malign
+cc-option-align = $(subst -functions=0,,\
+	$(call cc-option,-falign-functions=0,-malign-functions=0))
+
 # cc-version
 # Usage gcc-ver := $(call cc-version $(CC))
 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \

arch/i386/Makefile

@@ -25,7 +25,7 @@ CFLAGS += -pipe -msoft-float
 # prevent gcc from keeping the stack 16 byte aligned
 CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
 
-align := $(subst -functions=0,,$(call cc-option,-falign-functions=0,-malign-functions=0))
+align := $(cc-option-align)
 cflags-$(CONFIG_M386)		+= -march=i386
 cflags-$(CONFIG_M486)		+= -march=i486
 cflags-$(CONFIG_M586)		+= -march=i586