#ifndef _GLOB_H
#define _GLOB_H 1
-#ifndef MISSING_SYS_CDEFS_H
+/* Note the reversal of the common HAVE_SYS_CDEFS_H idiom below. In this
+ way, #ifndef _SYS_CDEFS_H may be used to include <sys/cdefs.h> both when
+ it has been checked for via the GNULIB configure test and found and when
+ it has not been checked for, which we can presume means that the <glob.h>
+ GNULIB shares with GLIBC is being included as a system header and not as
+ part of GNULIB, in which case <sys/cdefs.h> may be assumed. */
+#ifndef _SYS_CDEFS_H
# include <sys/cdefs.h>
#endif
#ifndef __BEGIN_DECLS