* configure.ac (CFLAGS_FOR_BUILD, CXXFLAGS_FOR_BUILD, LDFLAGS_FOR_BUILD): Default them to host flags only
  for $host = $build.
  Set default CXXFLAGS_FOR_BUILD to CXXFLAGS, not CFLAGS.
  Set default LDFLAGS_FOR_BUILD to LDFLAGS, not CFLAGS.
* configure: Regenerate.

From-SVN: r129122