Previously, the cast was implicit since abs() takes an int,
so there is no change in behaviour.
Suppresses a clang warning that we might want fabs().
git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1451 af15c1b1-3010-417e-b628-4374ebc0bcbd