Merge branch 'msvc' into master

Merge branch 'msvc' into master

Commits merged from msvc:
 - warnings: fix buglets for portability warnings
 - tests: extend tests on 'extra-portability' warning category

Extra testsuite edits:
* tests/extra-portability3.test: Use `$original_AUTOMAKE' instead
of hackishly extracting the first component of `$AUTOMAKE'.
* tests/extra-portability.test: Likewise.  Also, since we are at
it, throw in a couple of small extensions and tweakings (suggested
by the minor merge conflicts).