- AC_CACHE_CHECK([for wint_t], gt_cv_c_wint_t,
- [AC_TRY_COMPILE([#include <wchar.h>
+ AC_CACHE_CHECK([for wint_t], [gt_cv_c_wint_t],
+ [AC_TRY_COMPILE([
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+ <wchar.h>.
+ BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
+ before <wchar.h>. */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>