In particular, conditional expressions which contain an
assignment statement, where the expression type is not
explicitly made to be boolean, elicits the following
message:
    warning 2: possible unintended assignment

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>