EDIT: And why does quake decide to rename all opengl funcs with a q infront of them? Theres a whole header full of #define qfunc_name func_name
MicroSoft thought that just linking to libopengl would be too easy for real programmers, so all post-OpenGL 1.1 functions are only available by getting their function pointer through wglGetProcAddress.
The engine obtains all function pointers in the InitOpenGL function and stores them in variables named like the corresponding function.
But if the function pointers were named just gl*, then of course there would be duplicate symbols for those OSes which export all GL functions, so they decided to use the qgl prefix for all OpenGL functions.
The gl functions which could be used directly are #defined with qgl prefix so that the programmers don't have to mess with different prefixes for direct and indirect GL functions.