dnl AC_GCC_VERSION
dnl check for compiler version
dnl sets COMPILER_VERSION and GCC_VERSION

AC_DEFUN([AC_CC_VERSION],
[
    AC_MSG_CHECKING([C compiler version])
    COMPILER_VERSION=`$CC -v 2>&1 | grep version`
    case "$COMPILER_VERSION" in
        *gcc*)
	   dnl Ok, how to turn $3 into the real $3
	   GCC_VERSION=`echo $COMPILER_VERSION | \
	   sed -e 's/[[^ ]]*\ [[^ ]]*\ \([[^ ]]*\)\ .*/\1/'` ;;
	*) GCC_VERSION=unknown ;;
    esac
    AC_MSG_RESULT($GCC_VERSION)
])

dnl AC_TRY_CCFLAG([CCFLAG], [VAR], [ACTION-IF-WORKS], [ACTION-IF-FAILS])
dnl check if $CC supports a given flag

AC_DEFUN([AC_TRY_CCFLAG],
[
    AC_REQUIRE([AC_PROG_CC])
    ac_save_CFLAGS=$CFLAGS
    CFLAGS=$1
    AC_CACHE_CHECK([whether $CC accepts $1 flag], [ac_cv_flag_$2],
	[AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
			   [AS_VAR_SET([ac_cv_flag_$2], [yes])],
			   [AS_VAR_SET([ac_cv_flag_$2], [no])])])
    CFLAGS=$ac_save_CFLAGS
    $2=AS_VAR_GET([ac_cv_flag_$2])
    if test "$2" = yes; then
        ifelse([$3], [], [:], [$3])
    else
        ifelse([$4], [], [:], [$4])
    fi
])

dnl AC_IF_YES([TEST-FOR-YES], [ACTION-IF-TRUE], [ACTION-IF-FALSE])
dnl AS_IF() abstraction, checks shell variable for 'yes'
AC_DEFUN([AC_IF_YES], [AS_IF([test $$1 = yes], [$2], [$3])])

dnl AC_TRY_LDFLAGS([LDFLAGS], [VAR], [ACTION-IF-WORKS], [ACTION-IF-FAILS])
dnl check if $CC supports given ld flags

AC_DEFUN([AC_TRY_LDFLAGS],
[
    AC_REQUIRE([AC_PROG_CC])
    ac_save_LDFLAGS=$LDFLAGS
    LDFLAGS=$1
	AC_CACHE_CHECK([whether $CC accepts $1 ld flags], [ac_cv_flag_$2],
	[AC_LINK_IFELSE([AC_LANG_PROGRAM()],
			[AS_VAR_SET([ac_cv_flag_$2], [yes])],
			[AS_VAR_SET([ac_cv_flag_$2], [no])])])
    LDFLAGS=$ac_save_LDFLAGS
    $2=AS_VAR_GET([ac_cv_flag_$2])
    if test "$2" = yes; then
        ifelse([$3], [], [:], [$3])
    else
        ifelse([$4], [], [:], [$4])
    fi
])


dnl PKG_CHECK_VAR(VARIABLE, MODULE, CONFIG-VARIABLE,
dnl [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
dnl -------------------------------------------
dnl Since: 0.28
dnl
dnl Retrieves the value of the pkg-config variable for the given module.
AC_DEFUN([PKG_CHECK_VAR],
[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
AC_ARG_VAR([$1], [value of $3 for $2, overriding pkg-config])dnl

_PKG_CONFIG([$1], [variable="][$3]["], [$2])
AS_VAR_COPY([$1], [pkg_cv_][$1])

AS_VAR_IF([$1], [""], [$5], [$4])dnl
])dnl PKG_CHECK_VAR


# ===========================================================================
#      http://www.gnu.org/software/autoconf-archive/ax_gcc_builtin.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_GCC_BUILTIN(BUILTIN)
#
# DESCRIPTION
#
#   This macro checks if the compiler supports one of GCC's built-in
#   functions; many other compilers also provide those same built-ins.
#
#   The BUILTIN parameter is the name of the built-in function.
#
#   If BUILTIN is supported define HAVE_<BUILTIN>. Keep in mind that since
#   builtins usually start with two underscores they will be copied over
#   into the HAVE_<BUILTIN> definition (e.g. HAVE___BUILTIN_EXPECT for
#   __builtin_expect()).
#
#   The macro caches its result in the ax_cv_have_<BUILTIN> variable (e.g.
#   ax_cv_have___builtin_expect).
#
#   The macro currently supports the following built-in functions:
#
#    __builtin_assume_aligned
#    __builtin_bswap16
#    __builtin_bswap32
#    __builtin_bswap64
#    __builtin_choose_expr
#    __builtin___clear_cache
#    __builtin_clrsb
#    __builtin_clrsbl
#    __builtin_clrsbll
#    __builtin_clz
#    __builtin_clzl
#    __builtin_clzll
#    __builtin_complex
#    __builtin_constant_p
#    __builtin_ctz
#    __builtin_ctzl
#    __builtin_ctzll
#    __builtin_expect
#    __builtin_ffs
#    __builtin_ffsl
#    __builtin_ffsll
#    __builtin_fpclassify
#    __builtin_huge_val
#    __builtin_huge_valf
#    __builtin_huge_vall
#    __builtin_inf
#    __builtin_infd128
#    __builtin_infd32
#    __builtin_infd64
#    __builtin_inff
#    __builtin_infl
#    __builtin_isinf_sign
#    __builtin_nan
#    __builtin_nand128
#    __builtin_nand32
#    __builtin_nand64
#    __builtin_nanf
#    __builtin_nanl
#    __builtin_nans
#    __builtin_nansf
#    __builtin_nansl
#    __builtin_object_size
#    __builtin_parity
#    __builtin_parityl
#    __builtin_parityll
#    __builtin_popcount
#    __builtin_popcountl
#    __builtin_popcountll
#    __builtin_powi
#    __builtin_powif
#    __builtin_powil
#    __builtin_prefetch
#    __builtin_trap
#    __builtin_types_compatible_p
#    __builtin_unreachable
#
#   Unsuppored built-ins will be tested with an empty parameter set and the
#   result of the check might be wrong or meaningless so use with care.
#
# LICENSE
#
#   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
#
#   Copying and distribution of this file, with or without modification, are
#   permitted in any medium without royalty provided the copyright notice
#   and this notice are preserved.  This file is offered as-is, without any
#   warranty.

serial 3

AC_DEFUN([AX_GCC_BUILTIN], [
    AS_VAR_PUSHDEF([ac_var], [ax_cv_have_$1])

    AC_CACHE_CHECK([for $1], [ac_var], [
        AC_LINK_IFELSE([AC_LANG_PROGRAM([], [
            m4_case([$1],
                [__builtin_assume_aligned], [$1("", 0)],
                [__builtin_bswap16], [$1(0)],
                [__builtin_bswap32], [$1(0)],
                [__builtin_bswap64], [$1(0)],
                [__builtin_choose_expr], [$1(0, 0, 0)],
                [__builtin___clear_cache], [$1("", "")],
                [__builtin_clrsb], [$1(0)],
                [__builtin_clrsbl], [$1(0)],
                [__builtin_clrsbll], [$1(0)],
                [__builtin_clz], [$1(0)],
                [__builtin_clzl], [$1(0)],
                [__builtin_clzll], [$1(0)],
                [__builtin_complex], [$1(0.0, 0.0)],
                [__builtin_constant_p], [$1(0)],
                [__builtin_ctz], [$1(0)],
                [__builtin_ctzl], [$1(0)],
                [__builtin_ctzll], [$1(0)],
                [__builtin_expect], [$1(0, 0)],
                [__builtin_ffs], [$1(0)],
                [__builtin_ffsl], [$1(0)],
                [__builtin_ffsll], [$1(0)],
                [__builtin_fpclassify], [$1(0, 1, 2, 3, 4, 0.0)],
                [__builtin_huge_val], [$1()],
                [__builtin_huge_valf], [$1()],
                [__builtin_huge_vall], [$1()],
                [__builtin_inf], [$1()],
                [__builtin_infd128], [$1()],
                [__builtin_infd32], [$1()],
                [__builtin_infd64], [$1()],
                [__builtin_inff], [$1()],
                [__builtin_infl], [$1()],
                [__builtin_isinf_sign], [$1(0.0)],
                [__builtin_nan], [$1("")],
                [__builtin_nand128], [$1("")],
                [__builtin_nand32], [$1("")],
                [__builtin_nand64], [$1("")],
                [__builtin_nanf], [$1("")],
                [__builtin_nanl], [$1("")],
                [__builtin_nans], [$1("")],
                [__builtin_nansf], [$1("")],
                [__builtin_nansl], [$1("")],
                [__builtin_object_size], [$1("", 0)],
                [__builtin_parity], [$1(0)],
                [__builtin_parityl], [$1(0)],
                [__builtin_parityll], [$1(0)],
                [__builtin_popcount], [$1(0)],
                [__builtin_popcountl], [$1(0)],
                [__builtin_popcountll], [$1(0)],
                [__builtin_powi], [$1(0, 0)],
                [__builtin_powif], [$1(0, 0)],
                [__builtin_powil], [$1(0, 0)],
                [__builtin_prefetch], [$1("")],
                [__builtin_trap], [$1()],
                [__builtin_types_compatible_p], [$1(int, int)],
                [__builtin_unreachable], [$1()],
                [m4_warn([syntax], [Unsupported built-in $1, the test may fail])
                 $1()]
            )
            ])],
            [AS_VAR_SET([ac_var], [yes])],
            [AS_VAR_SET([ac_var], [no])])
    ])

    AS_IF([test yes = AS_VAR_GET([ac_var])],
        [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_$1), 1,
            [Define to 1 if the system has the `$1' built-in function])], [])

    AS_VAR_POPDEF([ac_var])
])