[xemacs-hg @ 2005-01-26 10:33:40 by ben] Fix some race conditions in redisplay/signal redisplay.c, redisplay.h, signal.c: Move backtraces to internals manual. Fix some race conditions leading to crashes due to incomplete protection of critical sections. In signal.c, be more aggressive in catching incomplete critical section protection -- we cannot even check for QUIT, *EVER*, in a critical section.