Re: [PATCH] gl_CHECK_NEXT_HEADERS implies AC_CHECK_HEADERS_ONCE

[Bruno Haible]

Hi Paul,

> * m4/wctype_h.m4 (gl_WCTYPE_H): Likewise.

This part of the patch did something else: It changed an
gl_CHECK_NEXT_HEADERS invocation to gl_NEXT_HEADERS. But this means that
when the <wctype.h> header does not exist, NEXT_WCTYPE_H will not be set,
thus the gnulib-generated wctype.h replacement will contain

  #if 0
  # include 
  #endif

I'm not sure that all compilers support this. It's safer to write

  #if 0
  # include <wctype.h>
  #endif

This patch does it.


2011-01-23  Bruno Haible  <address@hidden>

        wctype: Ensure valid C syntax.
        * m4/wctype_h.m4 (gl_WCTYPE_H): Invoke gl_CHECK_NEXT_HEADERS
        unconditionally, instead of gl_NEXT_HEADERS conditionally.

--- m4/wctype_h.m4.orig Sun Jan 23 12:31:46 2011
+++ m4/wctype_h.m4      Sat Jan 22 01:44:29 2011
@@ -1,4 +1,4 @@
-# wctype_h.m4 serial 11
+# wctype_h.m4 serial 12
 
 dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
 
@@ -36,7 +36,6 @@
   AC_SUBST([HAVE_ISWBLANK])
   AC_SUBST([REPLACE_ISWBLANK])
 
-  AC_CHECK_HEADERS_ONCE([wctype.h])
   AC_REQUIRE([AC_C_INLINE])
 
   AC_REQUIRE([gt_TYPE_WINT_T])
@@ -47,6 +46,7 @@
   fi
   AC_SUBST([HAVE_WINT_T])
 
+  gl_CHECK_NEXT_HEADERS([wctype.h])
   if test $ac_cv_header_wctype_h = yes; then
     if test $ac_cv_func_iswcntrl = yes; then
       dnl Linux libc5 has an iswprint function that returns 0 for all 
arguments.
@@ -75,7 +75,6 @@
             ])
         ])
     fi
-    gl_NEXT_HEADERS([wctype.h])
     HAVE_WCTYPE_H=1
   else
     HAVE_WCTYPE_H=0