Homebrew and issue#1366

Several patches based on seeing info on issue#1366.

Removed warnings about wildcard *.nib and *.cns files.
Bootstrap appears permanently wired to have a config directory, therefore moved config.guess and config.sub into config/ and then updated both files to latest HEAD files.
Sanity check for pkg-config, halt bootstrap process if pkg-config is not installed.

Still need to figure-out the problem with:
configure.ac:671: error: required file 'lib/Makefile.in' not found
Makefile.am:62: error: required directory ./lib does not exist
as seen in issue#1344 since it also causes an exit with error here during bootstrap in issue#1366.