* m4/include_next.m4 (gl_INCLUDE_NEXT): Define and AC_SUBST

[pspp] / m4 / include_next.m4

diff --git a/m4/include_next.m4 b/m4/include_next.m4
index 62c5f3b3b5f8dd0c2a13c9599a2c58dea66ce7de..dfd5ec574ae04ce6bfccbe21f89f6ac26b3fc779 100644 (file)
--- a/m4/include_next.m4
+++ b/m4/include_next.m4
@@ -1,19 +1,79 @@
-# include_next.m4 serial 1
-dnl Copyright (C) 2006 Free Software Foundation, Inc.
+# include_next.m4 serial 2
+dnl Copyright (C) 2006, 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-dnl From Derek Price.
+dnl From Paul Eggert and Derek Price.
 
 AC_DEFUN([gl_INCLUDE_NEXT],
-[AC_CACHE_CHECK([whether the preprocessor supports include_next],
-[gl_cv_have_include_next],
-[AC_PREPROC_IFELSE([#include_next <stddef.h>],
-                   [gl_cv_have_include_next=yes],
-                   [gl_cv_have_include_next=no])])
-if test $gl_cv_have_include_next = yes; then
-  AC_DEFINE([HAVE_INCLUDE_NEXT], 1,
-            [Define if your compiler supports the #include_next directive.])
-fi
+[
+  AC_LANG_PREPROC_REQUIRE()
+  AC_CACHE_CHECK([whether the preprocessor supports include_next],
+    [gl_cv_have_include_next],
+    [AC_PREPROC_IFELSE([#include_next <stddef.h>],
+       [gl_cv_have_include_next=yes],
+       [gl_cv_have_include_next=no])])
+  if test $gl_cv_have_include_next = yes; then
+
+    dnl FIXME: Remove HAVE_INCLUDE_NEXT and update everything that uses it
+    dnl to use @INCLUDE_NEXT@ instead.
+    AC_DEFINE([HAVE_INCLUDE_NEXT], 1,
+             [Define if your compiler supports the #include_next directive.])
+
+    INCLUDE_NEXT=include_next
+  else
+    INCLUDE_NEXT=include
+  fi
+  AC_SUBST([INCLUDE_NEXT])
+])
+
+# gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)
+# ------------------------------------------
+# For each arg foo.h, if #include_next works, define NEXT_FOO_H to be
+# '<foo.h>'; otherwise define it to be
+# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
+# That way, a header file with the following line:
+#      #@INCLUDE_NEXT@ @NEXT_FOO_H@
+# behaves (after sed substitution) as if it contained
+#      #include_next <foo.h>
+# even if the compiler does not support include_next.
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use `""', not `<>', so that the /// cannot be confused with a C99 comment.
+AC_DEFUN([gl_CHECK_NEXT_HEADERS],
+[
+  AC_REQUIRE([gl_INCLUDE_NEXT])
+  AC_CHECK_HEADERS_ONCE([$1])
+
+  AC_FOREACH([gl_HEADER_NAME], [$1],
+    [AS_VAR_PUSHDEF([gl_next_header],
+                   [gl_cv_next_]m4_quote(m4_defn([gl_HEADER_NAME])))
+     AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
+     if test $gl_cv_have_include_next = no; then
+       AC_CACHE_CHECK(
+        [absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
+        m4_quote(m4_defn([gl_next_header])),
+        [if test AS_VAR_GET([ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME]))) = yes; then
+           AC_LANG_CONFTEST(
+             [AC_LANG_SOURCE(
+                [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
+              )])
+           dnl eval is necessary to expand ac_cpp.
+           dnl Ultrix and Pyramid sh refuse to redirect output of eval,
+           dnl so use subshell.
+           AS_VAR_SET([gl_next_header],
+             ['"'`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+              sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{
+                s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#
+                s#^/[^/]#//&#
+                p
+                q
+              }'`'"'])
+         fi])
+     fi
+     AC_SUBST(
+       AS_TR_CPP([NEXT_]m4_quote(m4_defn([gl_HEADER_NAME]))),
+       [AS_VAR_GET([gl_next_header])])
+     AS_VAR_POPDEF([gl_next_header])])
 ])