[PATCH] uml: UML/i386 cmpxchg fix

Using native cmpxchg offers a slight performance improvement in uml/i386.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/Kconfig.i386

@@ -42,3 +42,7 @@ config ARCH_HAS_SC_SIGNALS
 config ARCH_REUSE_HOST_VSYSCALL_AREA
 	bool
 	default y
+
+config X86_CMPXCHG
+	bool
+	default y

include/asm-um/system-i386.h

@@ -3,6 +3,4 @@
 
 #include "asm/system-generic.h"
     
-#define __HAVE_ARCH_CMPXCHG 1
-
 #endif