Skip preprocessor check in AC_CHECK_HEADERS_ONCE.

* lib/autoconf/headers.m4 (_AC_HEADERS_EXPANSION): Provide fourth
argument to speed up check.

Signed-off-by: Eric Blake <ebb9@byu.net>

diff --git a/ChangeLog b/ChangeLog
index 34a61c6be695c15bbfab8b23b80b6f1094713e86..9c92ab266dd12c37ea0cf10708a68a95eaad747a 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-11-06  Eric Blake  <ebb9@byu.net>
+
+       Skip preprocessor check in AC_CHECK_HEADERS_ONCE.
+       * lib/autoconf/headers.m4 (_AC_HEADERS_EXPANSION): Provide fourth
+       argument to speed up check.
+
 2008-11-06  Eric Blake  <ebb9@byu.net>
 
        Speed up AC_CHECK_TYPE.

diff --git a/lib/autoconf/headers.m4 b/lib/autoconf/headers.m4
index cb1cb9c8539f5569d38b8543fa62dc3d12a6857e..6802c38ae73d3ad467309d331b1a81018f51fae9 100644 (file)
--- a/lib/autoconf/headers.m4
+++ b/lib/autoconf/headers.m4
@@ -169,7 +169,7 @@ AS_VAR_POPDEF([ac_Header])])# _AC_CHECK_HEADER_MONGREL
 m4_define([_AC_CHECK_HEADER_COMPILE_BODY],
 [  AS_LINENO_PUSH([$[]1])
   AC_CACHE_CHECK([for $[]2], [$[]3],
-                [AC_COMPILE_IFELSE([AC_LANG_SOURCE([$[]4
+                [AC_COMPILE_IFELSE([AC_LANG_SOURCE([$[]4
 @%:@include <$[]2>])],
                                    [AS_VAR_SET([$[]3], [yes])],
                                    [AS_VAR_SET([$[]3], [no])])])
@@ -265,7 +265,7 @@ AC_DEFUN([AC_CHECK_HEADERS_ONCE],
 m4_define([_AC_HEADERS_EXPANSION],
 [
   m4_divert_text([DEFAULTS], [ac_header_list=])
-  AC_CHECK_HEADERS([$ac_header_list])
+  AC_CHECK_HEADERS([$ac_header_list], [], [], [AC_INCLUDES_DEFAULT])
   m4_define([_AC_HEADERS_EXPANSION], [])
 ])