Merge upstream r825: fix line continuation in whitespace
Perform more checks on the number of tables supplied by user.
sh: Allow backslash-newline continuation in more places:

 * directly after a $
 * directly after ${
 * between the characters of a multi-character operator token
 * within a parameter name
Merge remote-tracking branch 'freebsd/master' into hardened/current/master
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/userlandenhanced