mapnik/mapnik — pull request #2360 by talaj (2014-08-17 12:38:02+00:00)
Title: fix compile with gcc

Mapnik cannot be compiled with gcc since value traits were introduced in 7b255f2b95958adeaf41daa55ec030f63293db6c.

This fixes the problem. Tested on Debian sid linux with gcc 4.9.1 and clang 3.6.