Merge branch 'ac-config-macro-dirs'

Merge branch 'ac-config-macro-dirs'

* ac-config-macro-dirs:
  news: we trace AC_CONFIG_MACRO_DIRS
  aclocal: trace AC_CONFIG_MACRO_DIR_TRACE
  aclocal: avoid spurious warnings from autom4te with AC_CONFIG_MACRO_DIRS
  coverage: expose a bug in aclocal (spurious warnings)
  aclocal: smash newlines in arguments of traced macros
  tests: better coverage for AC_CONFIG_MACRO_DIRS
  aclocal: diagnose non-existing directories in AC_CONFIG_MACRO_DIRS better
  aclocal: multiple local m4 macro dirs with AC_CONFIG_MACRO_DIRS