Fix #198 (CMake install path)

Use `PROJECT_NAME` instead of `CMAKE_PROJECT_NAME`

Author: utelle

CMakeLists.txt

@@ -356,7 +356,7 @@ set_target_properties(${SQLITE3MC_TARGET} PROPERTIES PUBLIC_HEADER "${SQLITE3MC_
 INSTALL(TARGETS ${SQLITE3MC_TARGET}
   ARCHIVE DESTINATION lib
   LIBRARY DESTINATION lib
-  PUBLIC_HEADER DESTINATION include/${CMAKE_PROJECT_NAME}
+  PUBLIC_HEADER DESTINATION include/${PROJECT_NAME}
   RUNTIME DESTINATION bin
 )
 
@@ -408,7 +408,7 @@ if(SQLITE3MC_BUILD_SHELL)
   INSTALL(TARGETS ${SQLITE3MC_SHELL_TARGET}
     ARCHIVE DESTINATION lib
     LIBRARY DESTINATION lib
-    PUBLIC_HEADER DESTINATION include/${CMAKE_PROJECT_NAME}
+    PUBLIC_HEADER DESTINATION include/${PROJECT_NAME}
     RUNTIME DESTINATION bin
   )
 endif()