[patch][gold] Fix pr18327

[Rafael Espíndola]

> Sorry, that's what I meant. The test failed for me with CXXLINK, but
> now I see that my GCC doesn't pass -static-libstdc++ to the linker.
>
> This is OK.

Pushed as cfbf0e3c5b637d66b2b1aeadecae9c187b825b2f. Thanks for the
review and sorry about the bug.

BTW, one peculiarity of the gold testsuite is that it is very
dependent on the host system: gcc, libstdc++ headers and libraries.
Wouldn't it be better to have the testsuite run ld directly and
checkin the .o files?

Cheers,
Rafael