diff --git a/configure.ac b/configure.ac
index f48db0733c..6b6dd0b9ba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -766,6 +766,7 @@ AS_CASE(["$target_os"],
 		AS_IF([test $gcc_major -lt 4 -o \( $gcc_major -eq 4 -a $gcc_minor -lt 3 \)], [
 		    ac_cv_func___builtin_setjmp=no
 		])
+		with_setjmp_type=sigsetjmp # to hijack SIGCHLD handler
 		AC_CACHE_CHECK(for broken crypt with 8bit chars, rb_cv_broken_crypt,
 		    [AC_TRY_RUN([
 #include <stdio.h>