diff --git a/import/setjmp.hb b/import/setjmp.hb
index 7e0ed6b..d58ca1f 100644
--- a/import/setjmp.hb
+++ b/import/setjmp.hb
@@ -1,7 +1,8 @@
 // setjmp.hb
 
-typedef char[160] jmp_buf;
-typedef char[160] sigjmp_buf;
+// sizeof(jmp_buf)==156 on Linux/i386/glibc2.3.
+typedef char[156] jmp_buf;
+typedef char[156] sigjmp_buf;
 
 extern int setjmp(jmp_buf buf);
 extern int sigsetjmp(sigjmp_buf buf, int savesigs);