Fix Compile on Linux with GCC.

"#include <maya/MTypes.h>" is needed to bring in some of the namespace
macros properly (in this case "OPENMAYA_EXPORT").

Author: david-cattermole

src/mmSolver/utilities/assert_utils.h

@@ -61,6 +61,7 @@
 #define MMASSERT_CXX_LINKER ::mmsolver::build_info::cxx_linker()
 
 // Maya
+#include <maya/MTypes.h>
 #include <maya/MStreamUtils.h>
 
 // MM Solver Libs