Its not posix compliant and serves very little purpose.
With this change compat and jobs modes are consistent wrt how
they treat each line of a script.
Add support for the '+' command line prefix as required by posix.
Lines prefixed with '+' are executed even when -n is given.
[Actually posix says they should also be done for -q and -t]
PR:
Reviewed by: jmc
This makes it possible to use expressions like
${("${LIST:Msomething"}):?present:absent}
it also makes treatment of lhs and rhs more consistent, and
makes CondToken easier to read.
Update unit-test/cond1 to test new features.
Also :tW and a W flag to :C and :S to allow treating value as a single word.
Add unit tests for the above, and fix some corner cases.
Based on patches supplied by Alan Barrett <apb@cequrux.com>