Visual C++ 6

[Jason Kraftcheck]

I've been trying to get Visual C++ 6 to work under Wine.  It does seem
to work for trivial programs with wine 0.9.6.  It fails to compile
anything with floating-point constants in the source because _atoldbl in
msvcrt.dll is not implemented.  I've attached a patch with a trivial
implementation of that function.  With the patch, I'm able to compile
trivial programs with floating-point math.  However, for any real
application, I'm getting internal compiler errors.