1. qmake Project Files: Declaring Other Libraries

2. If your program is exhausting memory then you have a memory leak. If that leak is unique to a version compiled with GCC then you only need to check the code paths that are unique to the program when compiled with GCC.

3. If the Microsoft compiler chokes on the source files from a library "based on MSVC in windows" then I suggest you take it up with the library author.