update zig build to latest master (#2910)

also, adds package manager support

build.zig

@@ -0,0 +1,18 @@
+const std = @import("std");
+const raylib = @import("src/build.zig");
+
+pub fn build(b: *std.Build) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+
+    const lib = raylib.addRaylib(b, target, optimize);
+    lib.installHeader("src/raylib.h", "raylib.h");
+    lib.install();
+}