When emerge x11-wm/ratpoison-1.4.7 without debug flag, him anyway configure with enabled debugging, seems when send --disable-debug option, configure accept it like --enable-debug, ratpoison configure don't have --disable-debug option. Reproducible: Always If remove line " $(use_enable debug) \" from ebuild, then ratpoison configuring normal.
Fixed in 1.4.7 and 9999. Thanks for the report!