CMake update to keep DirectXMath headers in their own include directory

Author: walbourn

CMakeLists.txt

@@ -30,7 +30,7 @@ add_library(${PROJECT_NAME} INTERFACE)
 
 target_include_directories(${PROJECT_NAME} INTERFACE
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/Inc>
-  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}>)
 
 #--- Package
 include(CMakePackageConfigHelpers)
@@ -58,7 +58,7 @@ install(EXPORT ${PROJECT_NAME}-targets
   DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/${PACKAGE_NAME}/cmake/)
 
 install(FILES ${LIBRARY_HEADERS}
-  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME})
 
 install(FILES
     ${CMAKE_CURRENT_BINARY_DIR}/${PACKAGE_NAME}-config.cmake