text: # warn-on-use.m4 serial 5
  dnl Copyright (C) 2010-2016 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.
  
  # gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES)
  # ---------------------------------------
  # For each whitespace-separated element in the list of NAMES, define
  # HAVE_RAW_DECL_name if the function has a declaration among INCLUDES
  # even after being undefined as a macro.
  #
  # See warn-on-use.h for some hints on how to poison function names, as
  # well as ideas on poisoning global variables and macros.  NAMES may
  # include global variables, but remember that only functions work with
  # _GL_WARN_ON_USE.  Typically, INCLUDES only needs to list a single
  # header, but if the replacement header pulls in other headers because
  # some systems declare functions in the wrong header, then INCLUDES
  # should do likewise.
  #
  # It is generally safe to assume declarations for functions declared
  # in the intersection of C89 and C11 (such as printf) without
  # needing gl_WARN_ON_USE_PREPARE.
  AC_DEFUN([gl_WARN_ON_USE_PREPARE],
  [
    m4_foreach_w([gl_decl], [$2],
      [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),
        [Define to 1 if ]m4_defn([gl_decl])[ is declared even after
         undefining macros.])])dnl
  dnl FIXME: gl_Symbol must be used unquoted until we can assume
  dnl autoconf 2.64 or newer.
    for gl_func in m4_flatten([$2]); do
      AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl
      AC_CACHE_CHECK([whether $gl_func is declared without a macro],
        gl_Symbol,
        [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
  [@%:@undef $gl_func
    (void) $gl_func;])],
          [AS_VAR_SET(gl_Symbol, [yes])], [AS_VAR_SET(gl_Symbol, [no])])])
      AS_VAR_IF(gl_Symbol, [yes],
        [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])
         dnl shortcut - if the raw declaration exists, then set a cache
         dnl variable to allow skipping any later AC_CHECK_DECL efforts
         eval ac_cv_have_decl_$gl_func=yes])
      AS_VAR_POPDEF([gl_Symbol])dnl
    done
  ])
  