Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -2247,10 +2247,24 @@
 		], [
 			AC_MSG_RESULT(yes)
 			OBJCFLAGS="$old_OBJCFLAGS"
 		])
 	])
+
+	AC_MSG_CHECKING(whether we need -Wno-strict-prototypes)
+	AC_COMPILE_IFELSE([
+		AC_LANG_PROGRAM([
+			#include <signal.h>
+		], [
+			signal(SIGINT, SIG_DFL);
+		])
+	], [
+		AC_MSG_RESULT(no)
+	], [
+		AC_MSG_RESULT(yes)
+		OBJCFLAGS="$OBJCFLAGS -Wno-strict-prototypes"
+	])
 
 	AS_IF([test x"$ac_cv_header_complex_h" = x"yes"], [
 		AC_MSG_CHECKING(whether we need -Wno-gnu-imaginary-constant)
 		AC_COMPILE_IFELSE([
 			AC_LANG_PROGRAM([