[cmake][X11] Add x11 libraries for raylib as glfw make private

[maiconpintoabreu]

Initial log: INFO: PLATFORM: DESKTOP (GLFW - X11): Initialized successfully
Quick Check

#if defined(_GLFW_X11)
    TraceLog(LOG_INFO, "BACKEND: X11");
#elif defined(_GLFW_WAYLAND)
    TraceLog(LOG_INFO, "BACKEND: Wayland");
#else
    TraceLog(LOG_WARNING, "BACKEND: Unknown");
#endif
#if defined(__linux__)
    TRACELOG(LOG_WARNING, "On LINUX");
#endif

CMAKE Result

WARNING: BACKEND: Unknown
WARNING: On LINUX

Make Result

INFO: BACKEND: X11
WARNING: On LINUX

The issue is because on Cmake the _GLFW_X11 is defined as PRIVATE and not readeable outside of the glfw library

[raysan5]

@maiconpintoabreu thanks for the review!