add raygui

zig/3rd-party/raygui

@@ -0,0 +1 @@
+Subproject commit 85a5c104f509b183c8cc7db0d90c2ab7a2b198c8

zig/build.zig

@@ -20,6 +20,7 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
+    exe.addIncludePath(.{ .path = "3rd-party/raygui/src" });
     exe.linkLibrary(raylib_dep.artifact("raylib"));
 
     // This declares intent for the executable to be installed into the

zig/src/main.zig

@@ -2,6 +2,10 @@ const std = @import("std");
 const raylib = @cImport({
     @cInclude("raylib.h");
 });
+const raygui = @cImport({
+    @cDefine("RAYGUI_IMPLEMENTATION", "1");
+    @cInclude("raygui.h");
+});
 
 pub fn main() !void {
     const screen_width = 800;
@@ -14,6 +18,7 @@ pub fn main() !void {
 
         raylib.ClearBackground(raylib.RAYWHITE);
         raylib.DrawText("Congrats! You created your first window!", 190, 200, 20, raylib.LIGHTGRAY);
+        if (raygui.GuiButton(.{ .x = 0, .y = 0, .width = 100, .height = 100 }, "MyButton") == 1) {}
     }
     raylib.CloseWindow();
 }