LGTM. Your changes are two commits, right?
https://codereview.appspot.com/575180043/diff/559180043/aclocal.m4 File aclocal.m4 (right): https://codereview.appspot.com/575180043/diff/559180043/aclocal.m4#newcode274 aclocal.m4:274: # "print a verbose error report and exit the program" Why quotation marks in the comment? https://codereview.appspot.com/575180043/