Merge branch 'msvc' into msvc-for-1.11

Merge branch 'msvc' into msvc-for-1.11

* msvc:
  tests: avoid a spurious failure of 'ltinit.test' MinGW
  tests: various minor tweakings, mostly related to AM_PROG_AR
  tests: testsuite is now safe to run with dmake in parallel mode
  tests: fix spurious failures w.r.t. parallel make and colorization
  tests: fix spurious failure in 'distcheck-override-infodir.test'
  tests: avoid another failure of 'uninstall-fail.test' on Solaris
  ar-lib: fix configure output for "unrecognized archiver interface"
  warnings: fix buglets for portability warnings
  tests: extend tests on 'extra-portability' warning category