update external headers

ios/include/math/mat2.h

@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-#ifndef MATH_MAT2_H_
-#define MATH_MAT2_H_
+#ifndef TNT_MATH_MAT2_H
+#define TNT_MATH_MAT2_H
 
 #include <math/TMatHelpers.h>
-#include <math/vec2.h>
 #include <math/compiler.h>
+#include <math/vec2.h>
+
 #include <stdint.h>
 #include <sys/types.h>
 
@@ -358,4 +359,4 @@ constexpr void swap(filament::math::details::TMat22<T>& lhs,
 }
 }
 
-#endif  // MATH_MAT2_H_
+#endif  // TNT_MATH_MAT2_H