-shared-libgcc vs. -static -static-libgcc

[Benjamin Kosnik]

> What difference would it make?  It would end up being used for any C++
> compilation just the same, no?

The testsuite doesn't use CXXFLAGS. In general, it's easier to do arcane 
awk commands on CXXFLAGS than on CXX, which I try not to modify. Since 
-shared-libgcc seems like a flag, not a compiler invocation, I'd think it 
would be there anyway, but whatever.

Anyway, semantics need to be fixed anyway, regardless of how 
-shared-libgcc is propagated down to target libraries.

-benjamin