+Changes since 2.16: Added a -window-id argument to most hacks, so that they
+ can draw on arbitrary externally-provided windows.
+ Synched with xlockmore 4.11a01.
+ Added `flow' hack.
+ Added `atlantis' GL hack.
+ Renamed `puzzle' hack to `jigsaw', since xlock already
+ had a different mode called `puzzle'.
+ Made it self-configure properly when Motif 2.1.0 is
+ being used (requires -lXp now, sigh...)