Build setup for crossplatform SDL-based application

This is an example for building and running any app or game for all platform in C based on SDL3. Includes files and a build script to get SDL running on these platforms. Renders a red square on a black background when launched.

Platforms support:

• Linux
• macOS
• Windows (needs testing)
• Android
• iOS (compiled from macOS)

Bootstrap build system

cc nob.c -o nob

Usage and build programme:

1. Native:

• clang or gcc

2. iOS

• Xcode: xcrun, PlistBuddy, ibtool, security, codesign, devicectl, simctl

3. Android

• Java 17 (not higher)
• Android SDK
• Android NDK: javac, jar, d8, aapt2, zip, zipalign, apksigner
• ADB

TODO:

• Think if I should move env to an env.h or directly into nob.c
• Test on Windows