Moving from Windows to other OS'es may shock you at first, but with time you'll get used to it: You do not need a "platform" or "IDE" per se.
What you will need, is cmake, gcc/g++, a decent text editor and perhaps a debugger frontend.
Optionally you may find ctags useful, Doxygen, an svn repo and a profiler (such as Valgrind/KCachegrind).
I am unaware of how exactly you can port .net stuff to C/C++ (other than re-writing from scratch).
Linux and OSX have many similarities, so porting from one to another should not be that hard. Android is a different story, although C++ for android has become a possibility.
The closest thing to what you are looking for, would probably be Eclipse or Netbeans, but again, the simpler you keep those things, the better IMHO.