+
+ dnl Cygwin 1.7.2 btowc('\0') is WEOF, not 0.
+ AC_CACHE_CHECK([whether btowc(0) is correct],
+ [gl_cv_func_btowc_nul],
+ [
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#include <string.h>
+/* 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>
+int main ()
+{
+ if (btowc ('\0') != 0)
+ return 1;
+ return 0;
+}]])],
+ [gl_cv_func_btowc_nul=yes],
+ [gl_cv_func_btowc_nul=no],
+ [
+changequote(,)dnl
+ case "$host_os" in
+ # Guess no on Cygwin.
+ cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
+ # Guess yes otherwise.
+ *) gl_cv_func_btowc_nul="guessing yes" ;;
+ esac
+changequote([,])dnl
+ ])
+ ])
+
+ dnl IRIX 6.5 btowc(EOF) is 0xFF, not WEOF.