Use ${CMAKE_EXECUTALBE_SUFFIX} for extension of plutil on Windows

Author: yamoridon

CMakeLists.txt

@@ -584,12 +584,7 @@ install(FILES
           CoreFoundation/Base.subproj/module.map
         DESTINATION
           lib/swift/CoreFoundation)
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
-  set(plutil_executable plutil.exe)
-else()
-  set(plutil_executable plutil)
-endif()
 install(PROGRAMS
-          ${CMAKE_CURRENT_BINARY_DIR}/${plutil_executable}
+          ${CMAKE_CURRENT_BINARY_DIR}/plutil${CMAKE_EXECUTABLE_SUFFIX}
         DESTINATION
           ${CMAKE_INSTALL_FULL_BINDIR})