Suppressing GNULIB_TEST_MKTIME etc. in emacs/src/config.in

[Paul Eggert]

Now that Emacs is using a bit of gnulib, its src/config.in contains
three #undefs that look like this:

   /* Define to 1 when the gnulib module mktime should be tested. */
   #undef GNULIB_TEST_MKTIME

These symbols are unused by Emacs: it doesn't have gnulib tests and is not
likely to have them soon (we're trying for a light footprint here).
Maintainers look at Emacs's config.in file by hand more than they
do for other apps, and it'd be a bit nicer if these useless symbols
weren't there to confuse things.

So I'd like to remove these useless symbols from src/config.in.  One way to
do that, I suppose, would be to put the following into configure.in:

   AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], [])

This zaps the macro that generates the unwanted GNULIB_TEST_ indicators.

This seems quite a bit of a hack, though.  Are there better alternatives?
For example:

 * Define a new macro in gnulib that does the above AC_DEFUN, then
   invoke that macro in configure.in.

 * Add an optional parameter to gl_EARLY that causes it to do the
   above AC_DEFUN.

 * Modify gnulib-tool to generate the above AC_DEFUN if the user
   is not importing any test modules.

Any better ideas?  Or should I just quit while I'm ahead, and put that
one-liner into Emacs's configure.in with a comment explaining the
hack?