diff -urN linux-2.4.26/arch/i386/Makefile linux/arch/i386/Makefile
--- linux-2.4.26/arch/i386/Makefile	2003-06-13 14:51:29.000000000 +0000
+++ linux/arch/i386/Makefile	2004-06-25 00:36:14.000000000 +0000
@@ -53,11 +53,11 @@
 endif
 
 ifdef CONFIG_MPENTIUMIII
-CFLAGS += -march=i686
+CFLAGS += $(call check_gcc,-march=pentium3,-march=i686)
 endif
 
 ifdef CONFIG_MPENTIUM4
-CFLAGS += -march=i686
+CFLAGS += $(call check_gcc,-march=pentium4,-march=i686)
 endif
 
 ifdef CONFIG_MK6