made quakespasm custom conback embedding optional, still defaulting to 1. the code requires USE_QS_CONBACK preprocessor definition. git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@392 af15c1b1-3010-417e-b628-4374ebc0bcbd
git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@52 af15c1b1-3010-417e-b628-4374ebc0bcbd