glfw: add basic example, building+linking on macOS is working

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

glfw/src/main.zig

@@ -0,0 +1,28 @@
+const std = @import("std");
+const testing = std.testing;
+
+const c = @cImport(@cInclude("GLFW/glfw3.h"));
+
+pub fn basicTest() void {
+    if (c.glfwInit() != c.GLFW_TRUE) {
+        @panic("failed to init");
+    }
+    const window = c.glfwCreateWindow(640, 480, "GLFW example", null, null);
+    if (window == null)
+    {
+        c.glfwTerminate();
+        @panic("failed to create window");
+    }
+
+    var start = std.time.milliTimestamp();
+    while (std.time.milliTimestamp() < start+3000 and c.glfwWindowShouldClose(window) != c.GLFW_TRUE) {
+        c.glfwPollEvents();
+    }
+
+    c.glfwDestroyWindow(window);
+    c.glfwTerminate();
+}
+
+test "basic" {
+    basicTest();
+}