Can't build with cc on Solaris

[Alexandre Oliva]

binutils top-level configure passes --with-gnu-ld down to sub-projects
`configure' commands whenever it finds `ld' is going to be built.
This causes libtool's `configure' fragment and `ltconfig' to search
for GNU ld whenever the compiler is not GCC.  If it can't find a GNU
ld, it will just bail out.  I currently don't have a solution for this
problem, but one possible work-around is to arrange that the top-level
configure passes `--with-gnu-ld=build' down to sub-projects.  I
haven't verified whether this works correctly so far.

The second problem, in the same scenario, is that, when libtool finds
GNU ld, it will assume that the compiler uses it.  This assumption is
wrong, and causes an --enable-shared build to break.  I've just come
up with a candidate solution for this problem: ltconfig will check
whether the selected compiler actually uses GNU ld.  If not, it will
just refrain from using any GNU ld-specific knowledge.  This is not
perfect, but it should work for now.  I'll try to find some better
solution for libtool 1.4+.  Meanwhile, ok to install this one in the
Sourceware CVS tree?  In the binutils release branch?