Merge branch 'msvc-for-1.11' into branch-1.11

Merge branch 'msvc-for-1.11' into branch-1.11

* msvc-for-1.11: (26 commits)
  tests: fix broken backport of tests on `extra-portability' warnings
  tests: various minor tweakings, mostly related to AM_PROG_AR
  tests: fix broken backport of AM_PROG_AR tests
  ar-lib: fix configure output for "unrecognized archiver interface"
  warnings: fix buglets for portability warnings
  tests: extend tests on 'extra-portability' warning category
  warnings: 'extra-portability' category is not implied by '-Wall'
  tests: various minor tweakings, mostly related to AM_PROG_AR
  tests: few improvements to some `ar-lib' related tests
  warnings: new 'extra-portability' category, for AM_PROG_AR
  ar-lib: new 'AM_PROG_AR' macro, triggering the 'ar-lib' script
  Skip MSVC oriented tests if the shell is not capable.
  Fix latest ChangeLog entries.
  lib/compile: update scriptversion.
  compile: clear the `eat' variable earlier.
  depcomp: add new one-pass depmode for MSVC 7 and later.
  tests: fix ar-lib.test for echo that interprets backslashes.
  compile: implement library search to support MSVC static linking
  Make ar-lib support backslashed files in archives.
  Do file name conversion for object files in the compile wrapper.
  ...