[build.zig] X11-only systems fail builds by default

[lnc3l0t]

• this PR references the [build.zig] GLFW Platform Detection Support #4150 (comment)

I added a check to find the program wayland-scanner, if it's not found the following error log is printed and the build fails:

 Wayland may not be installed on the system.
 You can switch to X11 in your `build.zig` by changing `Options.linux_display_backend`

• NOTE: in zig 0.14.0 it will be possible to add a failure message directly to a failed step (std.Build: Add Step.Fail and addFail() function. ziglang/zig#20312). It is not needed, but I reference it here for the future.

[raysan5]

@lnc3l0t thanks for the improvement!