autoconf: make sure 'restrict' keyword is always available

diff --git a/m4/usual.m4 b/m4/usual.m4
index 5d61bcecf7d82c0b28c09349b3db4e6fe77aff9f..08cadccd421584f664c202cf2f1d1fa2298a62a0 100644 (file)
--- a/m4/usual.m4
+++ b/m4/usual.m4
@@ -99,6 +99,7 @@ dnl AC_USUAL_TYPE_CHECK: Basic types for C
 dnl
 AC_DEFUN([AC_USUAL_TYPE_CHECK], [
 AC_C_INLINE
+AC_C_RESTRICT
 AC_C_BIGENDIAN
 AC_SYS_LARGEFILE
 AC_TYPE_PID_T