gcc-wrapper: Put arguments into a response file.

Creates a response file with arguments encoded as "'$escapedArg'" and
separated by newlines.

The current integration now _always_ creates a response file, because we
don't yet check whether the input actually contained a response file in
the first place.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
gcc-wrapper: Only create response file if needed.

The function expandResponseFileArgs() already checks whether expansion
is needed, so let's take that into account in runWithExpandedArgs().

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
gcc-wrapper: Rename runWithExpandedArgs.

Now being called runWithUnexpandedArgs, it actually matches
expandResponseFileArgs with its naming scheme, as it is doing more or
less the opposite.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>