aboutsummaryrefslogtreecommitdiff
path: root/misc/sys/cdefs.h
diff options
context:
space:
mode:
Diffstat (limited to 'misc/sys/cdefs.h')
-rw-r--r--misc/sys/cdefs.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 36510effe1..5880fe9c5e 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -21,7 +21,14 @@
/* We are almost always included from features.h. */
#ifndef _FEATURES_H
-#include <features.h>
+# include <features.h>
+#endif
+
+/* The GNU libc does not support any K&R compilers or the traditional mode
+ of ISO C compilers anymore. Check for some of the combinations not
+ anymore supported. */
+#if defined __GNUC__ && !defined __STDC__
+# error "You need a ISO C conforming compiler to use the glibc headers"
#endif
/* Some user header file might have defined this before. */