Don't do anything if sorter was replaced, even for one tick only. Hopefully fixes
issue #907, but not confirmed, though very highly plausible.
if(WIN32 AND NOT UNIX)
file(GLOB DLLs *.dll)
file(GLOB ICOs *.ico)
install(FILES
${DLLs}
${ICOs}
DESTINATION ${target_library_install_dir})
endif(WIN32 AND NOT UNIX)