Make make a little bit more POSIXish with regard to option parsing:

Make make a little bit more POSIXish with regard to option parsing:
take everything after -- as either a macro assignment or a target.
Note that make still reorders arguments before --: anything starting
with a dash is considered an option, anything which contains an equal
sign is considered a macro assignment and everything else a target.
This still is not POSIX with regard to the options, but it will probably
not change because it has been make's behaviour for ages.
Add a new function Var_Match() that correctly skips a macro call by just
doing the same as Var_Subst() but without producing output. This will help
making the parser more robust.

Patches:	7.190,7.191
Submitted by:	Max Okumoto <okumoto@ucsd.edu>