diff --git a/src/x86/siglongjmp-x86.S b/src/x86/siglongjmp-x86.S
index 194f2053..ff64acef 100644
--- a/src/x86/siglongjmp-x86.S
+++ b/src/x86/siglongjmp-x86.S
@@ -1 +1,7 @@
-# warning Implement me.
+	/* Dummy implementation for now.  Libunwind-based setjmp/longjmp
+	   can't work on x86 until we take advantage of DWARF2 unwind info.  */
+
+	.globl _UI_siglongjmp_cont
+
+_UI_siglongjmp_cont:
+	ret