Index: /trunk/source/lisp-kernel/x86-exceptions.c
===================================================================
--- /trunk/source/lisp-kernel/x86-exceptions.c	(revision 14867)
+++ /trunk/source/lisp-kernel/x86-exceptions.c	(revision 14868)
@@ -2481,5 +2481,5 @@
    doesn't match what we expect; until that's fixed, we may need to
    account for this extra byte when adjusting the PC */
-#define LISP_ASSEMBLER_EXTRA_SIB_BYTE
+#undef LISP_ASSEMBLER_EXTRA_SIB_BYTE
 #define TCR_SEG_PREFIX 0x64