Switching from Borland C++

[Robert Krueger <rlkrueger sprynet com>]

Hello,
  I have been a C / C++ programmer for about 15 - 16 years, primarily
developing Windows applications using the Borland compilers exclusively,
the 
current one being C++ Builder 3.0.  
  I would like to continue to develop Windows 9x programs using C++ (not
with Borland C++ Builder), but would also like to dabble in Linux as
well.  I would like to be able to have a single set of tools that would
do for both OS's, if possible.
  I guess I still don't understand the relationship between the
many choices of GNU gcc, GTK+, GNOME, gtk--, etc.   I'm not sure what
fits
together. 
  When you purchase Borland C++ or VC++, everything comes in the
box. 
If I want to use C++ to develop Windows programs as well as Linux
programs, then I get lost in the choices.
  Could someone help straighten me out as to what tools I need for
C++ development for Windows 9x, and what tools for Linux?  Which ones
will overlap?

Any help would be appreciated.
Thankyou,
Robert Krueger