move to Module::Build and try basic clean up
update ppport.h
update typemap to new libstatgrab capabilities
regenerate const-*.inc for fallback ...
ExtUtils::Constant is in core since 5.7.3 ...

... and we're requiring 5.8.3 - so no fallback required anymore
bump version etc.
proper API using of search_libs ...
remove ExtUtils::Constant fallback ...
clean autoconf generated files, too
rely on Config::AutoConf - remove old check code
rework MANIFEST.SKIP