ax_prefix_config_h.m4 causes files to be left after "make distclean"

[David Bruce]

Hello Eric, Ralf et al,

We have reorganized our package (tuxmath) into a smaller package for
the game itself, plus a separate library package (t4k_common).  Both
packages use autotools, including autoheader.  As part of t4k_common,
we provide a couple of replacement functions (alphasort() and
scandir()) for platforms lacking these functions.  Thus, our
t4k_common.h header needs to have an autoheader include so it can
conditionally include the prototypes for these functions.

Since just putting #include "config.h" at the top of our library
header would cause a name collision with tuxmath's config.h, I have
used the ax_prefix_config_h.m4 macro to rename t4k_common's config.h
to "t4k_common-config.h", and adapted all the *.c files accordingly.

So far, so good - everything seems to work as documented.  The problem
is that "make distcheck" fails due to a failure of "make distclean":


make[1]: Leaving directory `/usr/local/src/git/t4kcommon/build'
rm -f config.status config.cache config.log configure.lineno
config.status.lineno
rm -f Makefile
ERROR: files left in build directory after distclean:
./t4k_common-config.h
./_configs.sed
make: *** [distcleancheck] Error 1

Relevant code snippets:

>From configure.ac: -----------------

AC_CONFIG_HEADER([config.h])
dnl ------------- give config.h another name so it won't clash when
t4k_common.h included by tuxmath/tuxtype:
AX_PREFIX_CONFIG_H

>From t4k_globals.h (#included at top of every source file) -----------------

#include "t4k_common-config.h"

Sorry if there is something else I am supposed to be doing, but I
think I have followed the documentation and that there is a problem
with the behavior of ax_prefix_config_h.m4 with respect to "make
distclean"

Sincerely,

David Bruce