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223 lines
8.5 KiB
223 lines
8.5 KiB
# include_next.m4 serial 23 |
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dnl Copyright (C) 2006-2017 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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dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER. |
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dnl |
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dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to |
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dnl 'include' otherwise. |
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dnl |
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dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler |
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dnl supports it in the special case that it is the first include directive in |
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dnl the given file, or to 'include' otherwise. |
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dnl |
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dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next, |
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dnl so as to avoid GCC warnings when the gcc option -pedantic is used. |
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dnl '#pragma GCC system_header' has the same effect as if the file was found |
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dnl through the include search path specified with '-isystem' options (as |
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dnl opposed to the search path specified with '-I' options). Namely, gcc |
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dnl does not warn about some things, and on some systems (Solaris and Interix) |
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dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side |
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dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead |
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dnl of plain '__STDC__'. |
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dnl |
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dnl PRAGMA_COLUMNS can be used in files that override system header files, so |
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dnl as to avoid compilation errors on HP NonStop systems when the gnulib file |
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dnl is included by a system header file that does a "#pragma COLUMNS 80" (which |
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dnl has the effect of truncating the lines of that file and all files that it |
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dnl includes to 80 columns) and the gnulib file has lines longer than 80 |
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dnl columns. |
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AC_DEFUN([gl_INCLUDE_NEXT], |
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[ |
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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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[rm -rf conftestd1a conftestd1b conftestd2 |
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mkdir conftestd1a conftestd1b conftestd2 |
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dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on |
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dnl AIX 6.1 support include_next when used as first preprocessor directive |
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dnl in a file, but not when preceded by another include directive. Check |
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dnl for this bug by including <stdio.h>. |
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dnl Additionally, with this same compiler, include_next is a no-op when |
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dnl used in a header file that was included by specifying its absolute |
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dnl file name. Despite these two bugs, include_next is used in the |
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dnl compiler's <math.h>. By virtue of the second bug, we need to use |
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dnl include_next as well in this case. |
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cat <<EOF > conftestd1a/conftest.h |
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#define DEFINED_IN_CONFTESTD1 |
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#include_next <conftest.h> |
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#ifdef DEFINED_IN_CONFTESTD2 |
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int foo; |
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#else |
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#error "include_next doesn't work" |
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#endif |
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EOF |
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cat <<EOF > conftestd1b/conftest.h |
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#define DEFINED_IN_CONFTESTD1 |
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#include <stdio.h> |
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#include_next <conftest.h> |
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#ifdef DEFINED_IN_CONFTESTD2 |
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int foo; |
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#else |
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#error "include_next doesn't work" |
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#endif |
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EOF |
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cat <<EOF > conftestd2/conftest.h |
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#ifndef DEFINED_IN_CONFTESTD1 |
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#error "include_next test doesn't work" |
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#endif |
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#define DEFINED_IN_CONFTESTD2 |
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EOF |
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gl_save_CPPFLAGS="$CPPFLAGS" |
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CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2" |
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dnl We intentionally avoid using AC_LANG_SOURCE here. |
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AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
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[gl_cv_have_include_next=yes], |
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[CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2" |
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AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]], |
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[gl_cv_have_include_next=buggy], |
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[gl_cv_have_include_next=no]) |
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]) |
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CPPFLAGS="$gl_save_CPPFLAGS" |
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rm -rf conftestd1a conftestd1b conftestd2 |
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]) |
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PRAGMA_SYSTEM_HEADER= |
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if test $gl_cv_have_include_next = yes; then |
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INCLUDE_NEXT=include_next |
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INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
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if test -n "$GCC"; then |
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PRAGMA_SYSTEM_HEADER='#pragma GCC system_header' |
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fi |
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else |
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if test $gl_cv_have_include_next = buggy; then |
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INCLUDE_NEXT=include |
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INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next |
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else |
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INCLUDE_NEXT=include |
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INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include |
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fi |
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fi |
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AC_SUBST([INCLUDE_NEXT]) |
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AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE]) |
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AC_SUBST([PRAGMA_SYSTEM_HEADER]) |
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AC_CACHE_CHECK([whether system header files limit the line length], |
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[gl_cv_pragma_columns], |
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[dnl HP NonStop systems, which define __TANDEM, have this misfeature. |
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AC_EGREP_CPP([choke me], |
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[ |
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#ifdef __TANDEM |
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choke me |
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#endif |
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], |
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[gl_cv_pragma_columns=yes], |
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[gl_cv_pragma_columns=no]) |
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]) |
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if test $gl_cv_pragma_columns = yes; then |
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PRAGMA_COLUMNS="#pragma COLUMNS 10000" |
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else |
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PRAGMA_COLUMNS= |
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fi |
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AC_SUBST([PRAGMA_COLUMNS]) |
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]) |
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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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# Also, if #include_next works as first preprocessing directive in a file, |
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# define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to |
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# 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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# or |
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# #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_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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# Note: This macro assumes that the header file is not empty after |
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# preprocessing, i.e. it does not only define preprocessor macros but also |
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# provides some type/enum definitions or function/variable declarations. |
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# |
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# This macro also checks whether each header exists, by invoking |
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# AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument. |
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AC_DEFUN([gl_CHECK_NEXT_HEADERS], |
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[ |
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gl_NEXT_HEADERS_INTERNAL([$1], [check]) |
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]) |
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# gl_NEXT_HEADERS(HEADER1 HEADER2 ...) |
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# ------------------------------------ |
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# Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist. |
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# This is suitable for headers like <stddef.h> that are standardized by C89 |
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# and therefore can be assumed to exist. |
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AC_DEFUN([gl_NEXT_HEADERS], |
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[ |
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gl_NEXT_HEADERS_INTERNAL([$1], [assume]) |
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]) |
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# The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS. |
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AC_DEFUN([gl_NEXT_HEADERS_INTERNAL], |
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[ |
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AC_REQUIRE([gl_INCLUDE_NEXT]) |
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AC_REQUIRE([AC_CANONICAL_HOST]) |
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m4_if([$2], [check], |
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[AC_CHECK_HEADERS_ONCE([$1]) |
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]) |
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dnl FIXME: gl_next_header and gl_header_exists must be used unquoted |
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dnl until we can assume autoconf 2.64 or newer. |
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m4_foreach_w([gl_HEADER_NAME], [$1], |
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[AS_VAR_PUSHDEF([gl_next_header], |
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[gl_cv_next_]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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else |
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AC_CACHE_CHECK( |
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[absolute name of <]m4_defn([gl_HEADER_NAME])[>], |
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m4_defn([gl_next_header]), |
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[m4_if([$2], [check], |
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[AS_VAR_PUSHDEF([gl_header_exists], |
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[ac_cv_header_]m4_defn([gl_HEADER_NAME])) |
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if test AS_VAR_GET(gl_header_exists) = yes; then |
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AS_VAR_POPDEF([gl_header_exists]) |
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]) |
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gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME) |
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AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME)) |
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AS_VAR_SET(gl_next_header, ['"'$gl_header'"']) |
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m4_if([$2], [check], |
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[else |
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AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>']) |
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fi |
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]) |
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]) |
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fi |
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AC_SUBST( |
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AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])), |
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[AS_VAR_GET(gl_next_header)]) |
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if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then |
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# INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next' |
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gl_next_as_first_directive='<'gl_HEADER_NAME'>' |
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else |
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# INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include' |
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gl_next_as_first_directive=AS_VAR_GET(gl_next_header) |
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fi |
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AC_SUBST( |
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AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])), |
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[$gl_next_as_first_directive]) |
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AS_VAR_POPDEF([gl_next_header])]) |
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]) |
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# Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE; |
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# this fallback is safe for all earlier autoconf versions. |
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m4_define_default([AC_LANG_DEFINES_PROVIDED])
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