simplify code setting backing pixmap

[wxWidgets.git] / build / aclocal / ax_gcc_option.m4

# ===========================================================================
#             http://autoconf-archive.cryp.to/ax_gcc_option.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_GCC_OPTION(OPTION,EXTRA-OPTIONS,TEST-PROGRAM,ACTION-IF-SUCCESSFUL,ACTION-IF-NOT-SUCCESFUL)
#
# DESCRIPTION
#
#   AX_GCC_OPTION checks wheter gcc accepts the passed OPTION. If it accepts
#   the OPTION then ACTION-IF-SUCCESSFUL will be executed, otherwise
#   ACTION-IF-UNSUCCESSFUL.
#
#   NOTE: This macro will be obsoleted by AX_C_CHECK_FLAG AX_CXX_CHECK_FLAG,
#   AX_CPP_CHECK_FLAG, AX_CXXCPP_CHECK_FLAG and AX_LD_CHECK_FLAG.
#
#   A typical usage should be the following one:
#
#     AX_GCC_OPTION([-fomit-frame-pointer],[],[],[
#       AC_MSG_NOTICE([The option is supported])],[
#       AC_MSG_NOTICE([No luck this time])
#     ])
#
#   The macro doesn't discriminate between languages so, if you are testing
#   for an option that works for C++ but not for C you should use '-x c++'
#   as EXTRA-OPTIONS:
#
#     AX_GCC_OPTION([-fno-rtti],[-x c++],[],[ ... ],[ ... ])
#
#   OPTION is tested against the following code:
#
#     int main()
#     {
#             return 0;
#     }
#
#   The optional TEST-PROGRAM comes handy when the default main() is not
#   suited for the option being checked
#
#   So, if you need to test for -fstrict-prototypes option you should
#   probably use the macro as follows:
#
#     AX_GCC_OPTION([-fstrict-prototypes],[-x c++],[
#       int main(int argc, char ** argv)
#       {
#       	(void) argc;
#       	(void) argv;
#
#       	return 0;
#       }
#     ],[ ... ],[ ... ])
#
#   Note that the macro compiles but doesn't link the test program so it is
#   not suited for checking options that are passed to the linker, like:
#
#     -Wl,-L<a-library-path>
#
#   In order to avoid such kind of problems you should think about usinguse
#   the AX_*_CHECK_FLAG family macros
#
# LAST MODIFICATION
#
#   2008-04-12
#
# COPYLEFT
#
#   Copyright (c) 2008 Francesco Salvestrini <salvestrini@users.sourceforge.net>
#   Copyright (c) 2008 Bogdan Drozdowski <bogdandr@op.pl>
#
#   This program is free software; you can redistribute it and/or modify it
#   under the terms of the GNU General Public License as published by the
#   Free Software Foundation; either version 2 of the License, or (at your
#   option) any later version.
#
#   This program is distributed in the hope that it will be useful, but
#   WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
#   Public License for more details.
#
#   You should have received a copy of the GNU General Public License along
#   with this program. If not, see <http://www.gnu.org/licenses/>.
#
#   As a special exception, the respective Autoconf Macro's copyright owner
#   gives unlimited permission to copy, distribute and modify the configure
#   scripts that are the output of Autoconf when processing the Macro. You
#   need not follow the terms of the GNU General Public License when using
#   or distributing such scripts, even though portions of the text of the
#   Macro appear in them. The GNU General Public License (GPL) does govern
#   all other use of the material that constitutes the Autoconf Macro.
#
#   This special exception to the GPL applies to versions of the Autoconf
#   Macro released by the Autoconf Macro Archive. When you make and
#   distribute a modified version of the Autoconf Macro, you may extend this
#   special exception to the GPL to apply to your modified version as well.

AC_DEFUN([AX_GCC_OPTION], [
  AC_REQUIRE([AC_PROG_CC])

  AC_MSG_CHECKING([if gcc accepts $1 option])

  AS_IF([ test "x$GCC" = "xyes" ],[
    AS_IF([ test -z "$3" ],[
      ax_gcc_option_test="int main()
{
	return 0;
}"
    ],[
      ax_gcc_option_test="$3"
    ])

    # Dump the test program to file
    cat <<EOF > conftest.c
$ax_gcc_option_test
EOF

    # Dump back the file to the log, useful for debugging purposes
    AC_TRY_COMMAND(cat conftest.c 1>&AS_MESSAGE_LOG_FD)

    AS_IF([ AC_TRY_COMMAND($CC $2 $1 -c conftest.c 1>&AS_MESSAGE_LOG_FD) ],[
   	        AC_MSG_RESULT([yes])
    	$4
    ],[
   		AC_MSG_RESULT([no])
    	$5
    ])
  ],[
    AC_MSG_RESULT([no gcc available])
  ])
])