[MLton] commit r4911: Restored -{, target}-{as, cc, link}-opt behavior

[Matthew Fluet]

Reversed the behavior introduced by r4610.

The command switches -{,target}-{as,cc,link}-opt always tokenize their
argument on Char.isSpace, yeilding multiple gcc arguments.

The (new) command switches -{,target}-{as,cc,link}-opt-quote never
tokenize their argument, yeilding a single gcc argument.

Use the later if you need to pass include or library paths that have
spaces.


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U   mlton/trunk/bin/mlton-script
U   mlton/trunk/doc/changelog
U   mlton/trunk/mlton/main/main.fun
U   mlton/trunk/package/mingw/mlton.bat