Imported Upstream version 7.1.614
[packages/dc3dd.git] / m4 / include_next.m4
1 # include_next.m4 serial 6
2 dnl Copyright (C) 2006-2008 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
6
7 dnl From Paul Eggert and Derek Price.
8
9 AC_DEFUN([gl_INCLUDE_NEXT],
10 [
11   AC_LANG_PREPROC_REQUIRE()
12   AC_CACHE_CHECK([whether the preprocessor supports include_next],
13     [gl_cv_have_include_next],
14     [rm -rf conftestd1 conftestd2
15      mkdir conftestd1 conftestd2
16      cat <<EOF > conftestd1/conftest.h
17 #define DEFINED_IN_CONFTESTD1
18 #include_next <conftest.h>
19 #ifdef DEFINED_IN_CONFTESTD2
20 int foo;
21 #else
22 #error "include_next doesn't work"
23 #endif
24 EOF
25      cat <<EOF > conftestd2/conftest.h
26 #ifndef DEFINED_IN_CONFTESTD1
27 #error "include_next test doesn't work"
28 #endif
29 #define DEFINED_IN_CONFTESTD2
30 EOF
31      save_CPPFLAGS="$CPPFLAGS"
32      CPPFLAGS="$CPPFLAGS -Iconftestd1 -Iconftestd2"
33      AC_COMPILE_IFELSE([#include <conftest.h>],
34        [gl_cv_have_include_next=yes],
35        [gl_cv_have_include_next=no])
36      CPPFLAGS="$save_CPPFLAGS"
37      rm -rf conftestd1 conftestd2
38     ])
39   if test $gl_cv_have_include_next = yes; then
40
41     dnl FIXME: Remove HAVE_INCLUDE_NEXT and update everything that uses it
42     dnl to use @INCLUDE_NEXT@ instead.
43     AC_DEFINE([HAVE_INCLUDE_NEXT], 1,
44               [Define if your compiler supports the #include_next directive.])
45
46     INCLUDE_NEXT=include_next
47   else
48     INCLUDE_NEXT=include
49   fi
50   AC_SUBST([INCLUDE_NEXT])
51 ])
52
53 # gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)
54 # ------------------------------------------
55 # For each arg foo.h, if #include_next works, define NEXT_FOO_H to be
56 # '<foo.h>'; otherwise define it to be
57 # '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
58 # That way, a header file with the following line:
59 #       #@INCLUDE_NEXT@ @NEXT_FOO_H@
60 # behaves (after sed substitution) as if it contained
61 #       #include_next <foo.h>
62 # even if the compiler does not support include_next.
63 # The three "///" are to pacify Sun C 5.8, which otherwise would say
64 # "warning: #include of /usr/include/... may be non-portable".
65 # Use `""', not `<>', so that the /// cannot be confused with a C99 comment.
66 # Note: This macro assumes that the header file is not empty after
67 # preprocessing, i.e. it does not only define preprocessor macros but also
68 # provides some type/enum definitions or function/variable declarations.
69 AC_DEFUN([gl_CHECK_NEXT_HEADERS],
70 [
71   AC_REQUIRE([gl_INCLUDE_NEXT])
72   AC_CHECK_HEADERS_ONCE([$1])
73
74   m4_foreach_w([gl_HEADER_NAME], [$1],
75     [AS_VAR_PUSHDEF([gl_next_header],
76                     [gl_cv_next_]m4_quote(m4_defn([gl_HEADER_NAME])))
77      if test $gl_cv_have_include_next = yes; then
78        AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
79      else
80        AC_CACHE_CHECK(
81          [absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
82          m4_quote(m4_defn([gl_next_header])),
83          [AS_VAR_PUSHDEF([gl_header_exists],
84                          [ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME])))
85           if test AS_VAR_GET(gl_header_exists) = yes; then
86             AC_LANG_CONFTEST(
87               [AC_LANG_SOURCE(
88                  [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
89                )])
90             dnl eval is necessary to expand ac_cpp.
91             dnl Ultrix and Pyramid sh refuse to redirect output of eval,
92             dnl so use subshell.
93             AS_VAR_SET([gl_next_header],
94               ['"'`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
95                sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{
96                  s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#
97                  s#^/[^/]#//&#
98                  p
99                  q
100                }'`'"'])
101           else
102             AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
103           fi
104           AS_VAR_POPDEF([gl_header_exists])])
105      fi
106      AC_SUBST(
107        AS_TR_CPP([NEXT_]m4_quote(m4_defn([gl_HEADER_NAME]))),
108        [AS_VAR_GET([gl_next_header])])
109      AS_VAR_POPDEF([gl_next_header])])
110 ])