dnl Check whether limits.h has needed features.

dnl Copyright 2016-2018 Free Software Foundation, Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

dnl From Paul Eggert.

AC_DEFUN_ONCE([gl_LIMITS_H],

[

  gl_CHECK_NEXT_HEADERS([limits.h])

  AC_CACHE_CHECK([whether limits.h has ULLONG_WIDTH etc.],

    [gl_cv_header_limits_width],

    [AC_COMPILE_IFELSE(

       [AC_LANG_PROGRAM([[#ifndef __STDC_WANT_IEC_60559_BFP_EXT__

                           #define __STDC_WANT_IEC_60559_BFP_EXT__ 1

                          #endif

                          #include <limits.h>

                          int ullw = ULLONG_WIDTH;]])],

       [gl_cv_header_limits_width=yes],

       [gl_cv_header_limits_width=no])])

  if test "$gl_cv_header_limits_width" = yes; then

    LIMITS_H=

  else

    LIMITS_H=limits.h

  fi

  AC_SUBST([LIMITS_H])

  AM_CONDITIONAL([GL_GENERATE_LIMITS_H], [test -n "$LIMITS_H"])

])