Update Active Perl version to the one current "community edition".
Ensure that the autoconf and automake checked are the ones we install

rather than some random one installed elsewhere on the path.
Win32: Roll back Gwenhywfar to 4.9.0 to resolve broken build.

cc1.exe: warnings being treated as errors
In file included from c:/soft/aqbanking/include/aqbanking5/aqbanking/abgui.h:16:0,
                 from ../../../../repos/src/import-export/aqb/gnc-ab-utils.c:52:
c:/soft/gwenhywfar/include/gwenhywfar4/gwenhywfar/gui_be.h:60:10: error: 'libintl_printf' is an unrecognized format function type
make[5]: *** [gnc-ab-utils.lo] Error 1