[Automake-ng] Merge branch 'master' into ng/master

[Stefano Lattarini]

commit 9a0a106cf49cf8b1394cb800f9c7415e18958a54
Merge: aa8a4ca 3c66523
Author:     Stefano Lattarini <address@hidden>
AuthorDate: Tue Jan 31 10:59:28 2012 +0100
Commit:     Stefano Lattarini <address@hidden>
CommitDate: Tue Jan 31 11:11:27 2012 +0100

    Merge branch 'master' into ng/master

    * master:
      ar-lib: ignore the verbose modifier instead of erroring out
      scripts: cherry-pick recent changes from master
      maintcheck: fix real and spurious warnings
      maintcheck: take advantage of some GNU make features
      build: require GNU make in order to run the maintainer checks
      maintcheck: refactor rules checking '*.am' files
      tests: do not assume the object file extension is .o
      tests: fetch the 'compile' script for subdir objects
      tests: fetch the 'ar-lib' script for archiver usage
      tests: avoid spurious failure of 'transform2.test' on Cygwin
      tests: avoid spurious failure of deleted-am.test with FreeBSD make
      tests: avoid possibly undeserved PASS from check8.test
      tests: work around MinGW/MSYS issue in fd redirections
      warnings: more precise category and message for one warning
      release: revamp rules to tag and upload the releases
      amversion: add missing dependency
      hacking: update advice w.r.t. synced files
      hacking: don't reference ChangeLog anymore
      tests: add missing dependency for some 'ar-lib*.test' tests