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-rw-r--r--posix/getopt.h14
1 files changed, 10 insertions, 4 deletions
diff --git a/posix/getopt.h b/posix/getopt.h
index aec5d92a3d..12b7ad568e 100644
--- a/posix/getopt.h
+++ b/posix/getopt.h
@@ -23,10 +23,16 @@
# define _GETOPT_H 1
#endif
-/* We include this here since on system susing GNU libc we need some
- macros defined. <stdio.h> is probably the most portable header
- file and it does what we need. */
-#include <stdio.h>
+/* If __GNU_LIBRARY__ is not already defined, either we are being used
+ standalone, or this is the first header included in the source file.
+ If we are being used with glibc, we need to include <features.h>, but
+ that does not exist if we are standalone. So: if __GNU_LIBRARY__ is
+ not defined, include <ctype.h>, which will pull in <features.h> for us
+ if it's from glibc. (Why ctype.h? It's guaranteed to exist and it
+ doesn't flood the namespace with stuff the way some other headers do.) */
+#if !defined __GNU_LIBRARY__
+# include <ctype.h>
+#endif
#ifdef __cplusplus
extern "C" {