swift234

[Driver] Infer libFOO.dylib from a module name of FOO and vice versa.

(when in -emit-library mode)

The one catch is that if you specify an output file named "libFOO" with no
extension, the module name will still be "libFOO", not "FOO". Explicitly
providing both -o and -module-name is always allowed.

<rdar://problem/17827584>

Swift SVN r20869