~bzr-explorers/gnuhello/test : revision 240

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# include_next.m4 serial 6

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# include_next.m4 serial 9

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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 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 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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AC_DEFUN([gl_INCLUDE_NEXT],

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[

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AC_LANG_PREPROC_REQUIRE()

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[gl_cv_have_include_next],

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[rm -rf conftestd1 conftestd2

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mkdir conftestd1 conftestd2

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dnl The include of <stdio.h> is because IBM C 9.0 on AIX 6.1 supports

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dnl include_next when used as first preprocessor directive in a file,

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dnl but not when preceded by another include directive.

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cat <<EOF > conftestd1/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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CPPFLAGS="$save_CPPFLAGS"

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rm -rf conftestd1 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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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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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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INCLUDE_NEXT=include

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fi

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AC_SUBST([INCLUDE_NEXT])

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AC_SUBST([PRAGMA_SYSTEM_HEADER])

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])

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# gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)

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AC_DEFUN([gl_CHECK_NEXT_HEADERS],

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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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AC_CHECK_HEADERS_ONCE([$1])

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m4_foreach_w([gl_HEADER_NAME], [$1],

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[AC_LANG_SOURCE(

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[[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]

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)])

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dnl eval is necessary to expand ac_cpp.

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dnl AIX "xlc -E" and "cc -E" omit #line directives for header files

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dnl that contain only a #include of other header files and no

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dnl non-comment tokens of their own. This leads to a failure to

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dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>

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dnl and others. The workaround is to force preservation of comments

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dnl through option -C. This ensures all necessary #line directives

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dnl are present. GCC supports option -C as well.

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case "$host_os" in

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aix*) gl_absname_cpp="$ac_cpp -C" ;;

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*) gl_absname_cpp="$ac_cpp" ;;

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esac

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dnl eval is necessary to expand gl_absname_cpp.

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dnl Ultrix and Pyramid sh refuse to redirect output of eval,

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dnl so use subshell.

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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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['"'`(eval "$gl_absname_cpp conftest.$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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s#^/[^/]#//&#