cygwin ld import library issue fix (removing unused "_nm_" symbols)

[DJ Delorie]

> Don't you mean C99 style comments?

If I had meant C99, I would have said C99.

> Would be portable if the world adopted a standard now 2 years old...

You may dream all you like, but "portable" means "works on all the
systems we support".  We cannot control the systems.  We can control
our sources.  Portability precludes //-style comments in binutils.