-#if defined (__GNU_LIBRARY__) || defined (HAVE_STDLIB_H)
-/* Some stdlib.h (e.g., Solaris 2.7) declare putenv with a non-const argument.
- Since that would conflict with the declaration below, we rename putenv in
- that incompatible prototype. */
-# define putenv vendor_putenv_prototype
-# include <stdlib.h>
-# undef putenv
-#endif
-
-#if defined (__GNU_LIBRARY__) || defined (HAVE_STRING_H)
-# include <string.h>
-#endif
-#if defined (__GNU_LIBRARY__) || defined (HAVE_UNISTD_H)
-# include <unistd.h>
+/* Include errno.h *after* sys/types.h to work around header problems
+ on AIX 3.2.5. */
+#include <errno.h>
+#ifndef __set_errno
+# define __set_errno(ev) ((errno) = (ev))