dnl AC_TRY_CFLAGS (CFLAGS, [ACTION-IF-WORKS], [ACTION-IF-FAILS])
dnl check if $CC supports a given set of cflags
AC_DEFUN([AC_TRY_CFLAGS],
    [AC_MSG_CHECKING([if $CC supports $1 flags])
    SAVE_CFLAGS="$CFLAGS"
    CFLAGS="$1"
    AC_TRY_COMPILE([],[],[ac_cv_try_cflags_ok=yes],[ac_cv_try_cflags_ok=no])
    CFLAGS="$SAVE_CFLAGS"
    AC_MSG_RESULT([$ac_cv_try_cflags_ok])
    if test x"$ac_cv_try_cflags_ok" = x"yes"; then
        ifelse([$2],[],[:],[$2])
    else
        ifelse([$3],[],[:],[$3])
    fi])