Fix T39104: 2 clothes on a collision object cause crash

This was caused by static variables used in plNearestPoints().

For now solved by making the solvers allocated in the stack,
seems no noticeable affect on the simulation speed so far.

extern/bullet2/src/BulletDynamics/Dynamics/Bullet-C-API.cpp

@@ -354,11 +354,11 @@ double plNearestPoints(float p1[3], float p2[3], float p3[3], float q1[3], float
 	// btVoronoiSimplexSolver sGjkSimplexSolver;
 	// btGjkEpaPenetrationDepthSolver penSolverPtr;	
 	
-	static btSimplexSolverInterface sGjkSimplexSolver;
+	/*static*/ btSimplexSolverInterface sGjkSimplexSolver;
 	sGjkSimplexSolver.reset();
 	
-	static btGjkEpaPenetrationDepthSolver Solver0;
-	static btMinkowskiPenetrationDepthSolver Solver1;
+	/*static*/ btGjkEpaPenetrationDepthSolver Solver0;
+	/*static*/ btMinkowskiPenetrationDepthSolver Solver1;
 		
 	btConvexPenetrationDepthSolver* Solver = NULL;