# serial 1                                                   -*- Autoconf -*-

# BISON_AC_PROG_GNU_M4
# --------------------
# Check for GNU m4, at least 1.3 (supports frozen files).
AC_DEFUN([BISON_AC_PROG_GNU_M4],
[AC_PATH_PROGS(M4, gm4 gnum4 m4, m4)
AC_CACHE_CHECK([whether m4 supports frozen files],
               [ac_cv_prog_gnu_m4],
[ac_cv_prog_gnu_m4=no
if test x"$M4" != x; then
  case `$M4 --help < /dev/null 2>&1` in
    *reload-state*) ac_cv_prog_gnu_m4=yes ;;
  esac
fi])
])# BISON_AC_PROG_GNU_M4