Messed up gl_COMPILER_PREPARE_CHECK_DECL

[Mats Erik Andersson]

Hello there,

running autoreconf on OpenIndiana and on Debian GNU/Linux 8.8,
with the intent of rebuilding Inetutils, shatters with the message:

  error: AC_REQUIRE(gl_COMPILER_PREPARE_CHECK_DECL):
          cannot be used outside of an AC_DEFUN'd macro

Bruno Haible created this new macro on January 4th,
and Simon Josefsson was able to recreate Inetutils
on January 1st, so please check the text of this
new feature for any incompleteness or incompatibilities.

We are working on release candidates and need valid Gnulib!

Best regards,

  Mats Erik Andersson