ax_prog_flex.m4

# ===========================================================================
#       http://www.gnu.org/software/autoconf-archive/ax_prog_flex.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_PROG_FLEX(ACTION-IF-TRUE,ACTION-IF-FALSE)
#
# DESCRIPTION
#
#   Check whether flex is the scanner generator. Run ACTION-IF-TRUE if
#   successful, ACTION-IF-FALSE otherwise
#
# LICENSE
#
#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
#   Copyright (c) 2010 Diego Elio Petteno` <flameeyes@gmail.com>
#
#   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/>.
#
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#   gives unlimited permission to copy, distribute and modify the configure
#   scripts that are the output of Autoconf when processing the Macro. You
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#serial 12

# mattst88:
#     Replaced m4_ifnblank(...) with m4_ifval(m4_normalize(...), ...)
#     since m4_ifnblank requires autoconf-2.64.

AC_DEFUN([AX_PROG_FLEX], [
  AC_REQUIRE([AM_PROG_LEX])
  AC_REQUIRE([AC_PROG_EGREP])

  AC_CACHE_CHECK([if flex is the lexer generator],[ax_cv_prog_flex],[
    AS_IF([$LEX --version 2>/dev/null | $EGREP -qw '^g?flex'],
      [ax_cv_prog_flex=yes], [ax_cv_prog_flex=no])
  ])
  AS_IF([test "$ax_cv_prog_flex" = "yes"],
    m4_ifval(m4_normalize([$1]), [[$1]]),
    m4_ifval(m4_normalize([$2]), [[$2]])
  )
])