gcc: cleanup lib installation

[tonytheodore]

See:

• Downgrade gcc to 4.9 mxe/mxe#965
• mxe@c96a007#commitcomment-14323213

But I don't understand why additional make $(1).build/libcc1' is needed

libcc1 isn't in gcc-4.9, but a similar issue exists with shared libgcc. It's better to install correctly and remove erroneous files rather than moving them in case parallel builds write the same files.

Probably moving DLLs is needed for shared target only (and can be done without - in that case).

Done

Are they really needed in both locations?

No, they are no longer copied - gcc will find them using it's normal search path.

[starius]

Thanks!