AS_TMPDIR in _AC_PATH_PROG_FEATURE_CHECK, $debug

[Stepan Kasal]

Hello,
  I'd like to ask some questions about the usage of AS_TMPDIR in
autoconf generated scripts, as in _AC_PATH_PROG_FEATURE_CHECK.

AS_TMPDIR contains:

$debug || { trap '... rm -f -r $tmp ...' 0

But when one runs ./configure, debug in not set, so ``$debug''
suceeds and the trap is not set.
Perhaps we should set ``debug=false'' at the beginning of the configure
script.

But, if the trap were set, it would mean that the standard autoconf trap
is shadowed.
Perhaps the ``trap'' part of AS_TMPDIR should be disabled for autoconf?

As far as the _AC_PATH_PROG_FEATURE_CHECK macro is concerned, perhaps it
could do without the tmp dir?  Why couldn't _AC_FEATURE_CHECK_LENGTH work
in current directory?  It uses the names conftest.*, which are removed
by the autoconf cleanup at the end of the standard trap.

Have I missed something?

Regards,
        Stepan Kasal