Pathnames between #include files that are intended to be used within application code should not depend on the paths to the subdirectories being known to the compiler because this will not always be the case when an end-user includes your headers.

Includes of files in the local hierarchy must not use <...> please stick with "..."

src/LinearMath/btMatrix3x3.h

@@ -16,10 +16,10 @@ subject to the following restrictions:
 #ifndef btMatrix3x3_H
 #define btMatrix3x3_H
 
-#include "LinearMath/btScalar.h"
+#include "btScalar.h"
 
-#include "LinearMath/btVector3.h"
-#include "LinearMath/btQuaternion.h"
+#include "btVector3.h"
+#include "btQuaternion.h"
 
 
 class btMatrix3x3 {