I encountered a bug in the autogenerated 'autoconf-2.69/bin/autoscan' script which caused 'make check' to fail on test 503. The statement causing the problem is: s/\${[^\}]*}//g; which was at line 361 in my version. The diagnostic message was: "Unescaped left brace in regex is deprecated, ..." You can search [1]perldiag for that string (without the "...") to see the full message and its explanation. That deprecation was intoduced in v5.22: "[2]perl5220delta: A literal "{" should now be escaped in a pattern". Furthermore, the right brace in the character class does not need to be escaped. See "[3]perlrecharclass: Special Characters Inside a Bracketed Character Class". So, that problem line would be better as: s/\$\{[^}]*}//g; I did a quick test to demonstrate those points: $ perl -v | head -2 | tail -1 This is perl 5, version 24, subversion 0 (v5.24.0) built for darwin-thread-multi-2level $ perl -E 'say q/a${b}c/ =~ s/\${[^\}]*}//r' Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/\${ <-- HERE [^\}]*}/ at -e line 1. ac $ perl -E 'say q/a${b}c/ =~ s/\$\{[^}]*}//r' ac I edited my version of the 'autoscan' script manually; reran 'make check'; it completed without further problems. Cheers, Ken.
References 1. http://perldoc.perl.org/perldiag.html 2. http://perldoc.perl.org/perl5220delta.html#A-literal-%22%7b%22-should-now-be-escaped-in-a-pattern 3. http://perldoc.perl.org/perlrecharclass.html#Special-Characters-Inside-a-Bracketed-Character-Class