gtar 1.13.25: jm_CHECK_* autoconf macros fail on some platforms

[Christian Weisgerber]

I'm unhappy to report that the jm_CHECK_* autoconf macros in GNU
tar 1.13.2[345]'s configure.ac don't work on FreeBSD.

The problem is that something like this in configure.ac

    test $jm_cv_func_decl_free != yes
    AC_DEFINE_UNQUOTED(HAVE_DECL_FREE, $?,
      [Define to 1 if free is declared.])

turns into this shell fragment in configure:

    test $jm_cv_func_decl_free != yes

    cat >>confdefs.h <<EOF
    #define HAVE_DECL_FREE $?
    EOF

FreeBSD's /bin/sh resets $? when it starts evaluating the redirections,
so the symbol is always defined to 0 regardless of the previous
test result.  That probably qualifies as a shell bug, but it's not
going to disappear soon.  Other shells derived from 4.4BSD sh,
notably NetBSD's /bin/sh, also suffer from this.

-- 
Christian "naddy" Weisgerber                          address@hidden