sigsetjmp is macroized in some places, so use AC_TRY_LINK instead of

sigsetjmp is macroized in some places, so use AC_TRY_LINK instead of

Sun Nov  4 17:36:08 2001  Manish Singh  <yosh@gimp.org>

        * acconfig.h configure.in: sigsetjmp is macroized in some places,
        so use AC_TRY_LINK instead of AC_CHECK_FUNCS for the check.