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# include_next.m4 serial 3
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dnl Copyright (C) 2006, 2007 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl From Paul Eggert and Derek Price.
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AC_DEFUN([gl_INCLUDE_NEXT],
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AC_LANG_PREPROC_REQUIRE()
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AC_CACHE_CHECK([whether the preprocessor supports include_next],
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[gl_cv_have_include_next],
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[AC_PREPROC_IFELSE([#include_next <stddef.h>],
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[gl_cv_have_include_next=yes],
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[gl_cv_have_include_next=no])])
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if test $gl_cv_have_include_next = yes; then
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dnl FIXME: Remove HAVE_INCLUDE_NEXT and update everything that uses it
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dnl to use @INCLUDE_NEXT@ instead.
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AC_DEFINE([HAVE_INCLUDE_NEXT], 1,
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[Define if your compiler supports the #include_next directive.])
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INCLUDE_NEXT=include_next
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AC_SUBST([INCLUDE_NEXT])
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# gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)
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# ------------------------------------------
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# For each arg foo.h, if #include_next works, define NEXT_FOO_H to be
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# '<foo.h>'; otherwise define it to be
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# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
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# That way, a header file with the following line:
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# #@INCLUDE_NEXT@ @NEXT_FOO_H@
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# behaves (after sed substitution) as if it contained
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# #include_next <foo.h>
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# even if the compiler does not support include_next.
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# The three "///" are to pacify Sun C 5.8, which otherwise would say
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# "warning: #include of /usr/include/... may be non-portable".
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# Use `""', not `<>', so that the /// cannot be confused with a C99 comment.
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AC_DEFUN([gl_CHECK_NEXT_HEADERS],
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AC_REQUIRE([gl_INCLUDE_NEXT])
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AC_CHECK_HEADERS_ONCE([$1])
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AC_FOREACH([gl_HEADER_NAME], [$1],
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[AS_VAR_PUSHDEF([gl_next_header],
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[gl_cv_next_]m4_quote(m4_defn([gl_HEADER_NAME])))
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if test $gl_cv_have_include_next = yes; then
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AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
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[absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
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m4_quote(m4_defn([gl_next_header])),
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[AS_VAR_PUSHDEF([gl_header_exists],
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[ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME])))
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if test AS_VAR_GET(gl_header_exists) = yes; then
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[[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
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dnl eval is necessary to expand ac_cpp.
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dnl Ultrix and Pyramid sh refuse to redirect output of eval,
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AS_VAR_SET([gl_next_header],
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['"'`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
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sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{
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s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#
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AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
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AS_VAR_POPDEF([gl_header_exists])])
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AS_TR_CPP([NEXT_]m4_quote(m4_defn([gl_HEADER_NAME]))),
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[AS_VAR_GET([gl_next_header])])
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AS_VAR_POPDEF([gl_next_header])])
added
removed
m4/include_next.m4
