Back-compatibility bodges for the old tools provided by OpenIndiana.
(They don't even seem to have newer stuff in a ports system somewhere,
as far as I can tell.)

* autoconf is version 2.63
* libtool still wants to be invoked with AC_PROG_LIBTOOL not LT_INIT
* automake is indeed too old for an unconditional AM_SILENT_RULES
* pkg-config is not available at all AFAICT, which means we have to
  check in pkg.m4 so autoreconf can succeed