font.c exported three wrappers for one function, and the fit == -1 mode
existed only for the tests; textdraw() takes fit and colour. win.c
tested the empty picture in the thread and again in winshow, interned
two atoms by hand next to getatom(), kept a consumer-side drain that the
producer's already guarantees never finds anything, zeroed ten globals
before returning from the only thread that read them, and re-checked
sizes that resizebacking had just established. The page marker is laid
out once and drawn from the layout instead of being recomputed.
bits_per_rgb_value is the colormap component precision, not the pixel
layout; the NVIDIA driver reports 11 for its ordinary x8r8g8b8 visuals,
which left the popup disabled there. Depth, class, masks, byte order and
the pixmap format already pin the layout that putimage writes.
