trying to sort out the vectormath include path mess:

move vectormath to src folder, and add a vmInclude.h that contains the logic in a single location.
If you still need a system-wide vectormath, make sure to define USE_SYSTEM_VECTORMATH (in build system)

src/BulletMultiThreaded/btParallelConstraintSolver.cpp

@@ -21,8 +21,7 @@ subject to the following restrictions:
 #include "LinearMath/btQuickprof.h"
 #include "BulletMultiThreaded/btThreadSupportInterface.h"
 
-#include "vectormath_aos.h"
-
+#include "vectormath/vmInclude.h"
 
 #include "HeapManager.h"