update README and add cross compilation support

Author: srijan-paul

README.md

@@ -10,6 +10,34 @@ The project is  meant to serve as an example to anyone wanting to write their ow
     <img src="./screens/donkey-kong.png" alt="donkey kong gameplay" width="300px"/>
 </div>
 
+## Usage
+
+Make sure you have a ROM file in the iNES format.
+And definitely do not download ROMs from websites such as [this one](https://www.emulatorgames.net/roms/nintendo/),
+because that would be illegal (I think).
+
+To launch a ROM from the command line:
+
+```
+nez path/to/rom.nes 
+```
+
+To see debug info while playing the games:
+
+```
+nez --debug path/to/rom.nes
+```
+
+Controls:
+
+| Controller         | Keyboard   |
+|--------------------|------------|
+| A                  | Q          |
+| B                  | E          |
+| Start              | Enter      |
+| Select             | X          |
+| Up/Down/Left/Right | Arrow keys |
+
 ## Components
 
 ### The CPU: Ricoh-2A03
@@ -73,10 +101,6 @@ To play games, make sure you have a `.nes` file somewhere, and use:
  zig build run -- <path-to-rom>
  ```
 
-**NOTE:** Pirating ROMs is illegal, and I therefore highly recommend against going to websites like 
-[this](https://www.emulatorgames.net/roms/nintendo/)
-to download ROM files and open them in nez. 
-
 Oh, and only NROM  games are supported right now. So no contra, duck hunt, ninja gaiden, or darkwing duck, etc.
 
 The CPU has about ~10k test cases for each instruction, coming from [this awesome test repository](https://github.com/TomHarte/ProcessorTests/tree/main/nes6502).

build.zig

@@ -22,14 +22,22 @@ pub fn build(b: *std.Build) !void {
     const optimize = b.standardOptimizeOption(.{});
 
     const exe = b.addExecutable(.{
-        .name = "raylib-test",
+        .name = "nez",
         // In this case the main source file is merely a path, however, in more
         // complicated build scripts, this could be a generated file.
         .root_source_file = .{ .path = "src/main.zig" },
         .target = target,
         .optimize = optimize,
     });
 
+    if (target.isDarwin() and !target.isNative()) {
+        if (b.sysroot == null) {
+            @panic(" Pass --sysroot <path/to/macOS/SDK>");
+        }
+        exe.addSystemIncludePath(.{ .path = b.pathJoin(&.{ b.sysroot.?, "/usr/include" }) });
+        exe.addLibraryPath(.{ .path = b.pathJoin(&.{ b.sysroot.?, "/usr/lib" }) });
+        exe.addFrameworkPath(.{ .path = b.pathJoin(&.{ b.sysroot.?, "/System/Library/Frameworks" }) });
+    }
     raylib.addTo(b, exe, target, optimize);
     raygui.addTo(b, exe, target, optimize);
 

src/main.zig

@@ -91,12 +91,13 @@ const DebugView = struct {
 const debugFlag = "--debug";
 
 pub fn main() !void {
-    var args = std.process.args();
-    _ = args.skip();
-
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     var allocator = gpa.allocator();
 
+    var args = try std.process.argsWithAllocator(allocator);
+    defer args.deinit();
+    _ = args.skip();
+
     var isDebug = false;
     var flags: [2]?[:0]const u8 = undefined;