Fix finding ChangeLog when building

Keep the first optional argument of get_version.sh as "--strict" and
make the second the PROJECT_SOURCE_DIR plus trailing slash from
CMakeLists.txt

CMakeLists.txt

@@ -217,7 +217,7 @@ else()
   SET(ASAN_L_FLAGS "")
 endif()
 
-add_custom_target( version ALL "${PROJECT_SOURCE_DIR}/get_version.sh" "\"${PROJECT_SOURCE_DIR}\"" )
+add_custom_target( version ALL "${PROJECT_SOURCE_DIR}/get_version.sh" -- "\"${PROJECT_SOURCE_DIR}/\"" )
 
 link_directories( ${X11_LIBRARY_DIRS}
                   ${PANGOCAIRO_LIBRARY_DIRS}