diff -urNp --exclude CVS --exclude BitKeeper x-ref/arch/i386/Makefile x/arch/i386/Makefile
--- x-ref/arch/i386/Makefile	2003-04-05 05:18:25.000000000 +0200
+++ x/arch/i386/Makefile	2003-04-05 05:18:37.000000000 +0200
@@ -53,11 +53,11 @@ CFLAGS += -march=i686
 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