This trival patch adds support for GCC 3.1 -march=pentium{-mmx,3,4}
option and applies to both 2.4 and 2.5.

--- linux-vanilla/arch/i386/Makefile	Wed Apr 10 14:37:33 2002
+++ linux/arch/i386/Makefile	Sat May 25 22:53:08 2002
@@ -43,7 +43,7 @@
 endif
 
 ifdef CONFIG_M586MMX
-CFLAGS += -march=i586
+CFLAGS += $(shell if $(CC) -march=pentium-mmx -S -o /dev/null -xc /dev/null >/dev/null 2>&1; then echo "-march=pentium-mmx"; else echo "-march=i586"; fi)
 endif
 
 ifdef CONFIG_M686
@@ -51,11 +51,11 @@
 endif
 
 ifdef CONFIG_MPENTIUMIII
-CFLAGS += -march=i686
+CFLAGS += $(shell if $(CC) -march=pentium3 -S -o /dev/null -xc /dev/null >/dev/null 2>&1; then echo "-march=pentium3"; else echo "-march=i686"; fi)
 endif
 
 ifdef CONFIG_MPENTIUM4
-CFLAGS += -march=i686
+CFLAGS += $(shell if $(CC) -march=pentium4 -S -o /dev/null -xc /dev/null >/dev/null 2>&1; then echo "-march=pentium4"; else echo "-march=i686"; fi)
 endif
 
 ifdef CONFIG_MK6