Add QNX support
Created by: groleo
The patch set begins by fixing some minor issues, unrelated to QNX. Then, new functions are added to linux_platform for specifying GL library names; this is done to avoid adding ifdefs for lib names.
I've found a case where eglGetPlatformDisplay is available as a library symbol, but there's no EGL_PLATFORM_ enum for it, so it returns EGL_NONE.
The rest of the patch set adds a QNX screen platform, and makes the new backend available to wflinfo and examples.