It can be disabled by commenting out the #define STATIC_SIMULATION_ISLAND_OPTIMIZATION in Bullet/src/BulletCollision/CollisionDispatch/btUnionFind.h
See also Issue 406
Revert definition for ATTRIBUTE_ALIGNED16, and try to force sizeof(btSolverConstraint) by using unions with btScalar, for non-btScalar data types.
Use btAssert and not assert.
Don't access btAlignedObjectArray elements, for zero sets
boxbox reports contact point in B, rather then average point
box, cylinder use halfextents corrected for scaling and margin. made the margin in this halfextents explicit in the 'getHalfExtentsWithMargin' and 'getHalfExtentsWithoutMargin'
integrated changed for ODE quickstep solver
replaced inline with SIMD_FORCE_INLINE
some minor optimizations in the btSequentialImpulseConstraintSolver
added cone drawing (for X,Y,Z cones)
It leads to problems with certain compilers, when Bullet/src is located in a long pathname.
Keep include path starting with "LinearMath/, "BulletCollision/, or "BulletDynamics/