Native iPhone port of Factorio 2.0.77

Run the original macOS ARM64 game code on iOS:
- tools/retarget.py: header-only Mach-O retargeting to an iOS dylib
- platform/native: UIKit host and macOS API shims (AppKit for SDL's
  Cocoa backend, CoreGraphics displays, CoreAudio device, Metal device
  properties, Wuffs PNG decoding, Steam and peripheral stubs)
- touch, overlay, iOS keyboard and hardware keyboard input
- tools/build_native.py: build, sign, install, data copy, launch
- docs: build guide, controls, architecture

Also includes the earlier static-translation research (ARM64 -> WASM ->
native) under docs/research, runtime/, tests/ and tools/.

No game files are included; the build reads them from a local install.

tools/native_audit.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+"""Resolve every import of the macOS ARM64 slice against the iOS SDK's text stubs.
+
+Usage: python3 tools/native_audit.py build/factorio.arm64 [--json out.json]
+
+For each LC_LOAD_DYLIB the import is looked up in the iOS library with the same
+framework name, following re-exported libraries. Imports that do not resolve
+must be supplied by a shim. Nothing on the device is consulted, so this is a
+link-level audit only; Objective-C selectors are not checked.
+"""
+import json
+import re
+import subprocess
+import sys
+from pathlib import Path
+
+SDK = Path(subprocess.check_output(["xcrun", "--sdk", "iphoneos", "--show-sdk-path"], text=True).strip())
+
+
+def tbd_documents():
+    """Yield (install_name, symbols, reexports) for every tbd document in the SDK."""
+    files = list((SDK / "usr/lib").rglob("*.tbd")) + list((SDK / "System/Library").rglob("*.tbd"))
+    for path in files:
+        text = path.read_text(errors="ignore")
+        for doc in re.split(r"^--- !tapi-tbd", text, flags=re.M):
+            name = re.search(r"^install-name:\s*'?([^'\n]+)'?", doc, re.M)
+            if not name:
+                continue
+            exports = doc.split("\nreexports:")[0].split("\nundefineds:")[0]
+            symbols = set()
+            for kind, prefix in (("symbols", ""), ("weak-symbols", ""), ("thread-local-symbols", ""),
+                                 ("objc-classes", "class"), ("objc-eh-types", "eh"), ("objc-ivars", "ivar")):
+                for block in re.findall(rf"\b{kind}:\s*\[([^\]]*)\]", exports):
+                    for item in block.split(","):
+                        item = item.strip().strip("'\"")
+                        if not item:
+                            continue
+                        if prefix == "class":
+                            symbols.update({f"_OBJC_CLASS_$_{item}", f"_OBJC_METACLASS_$_{item}"})
+                        elif prefix == "eh":
+                            symbols.add(f"_OBJC_EHTYPE_$_{item}")
+                        elif prefix == "ivar":
+                            symbols.add(f"_OBJC_IVAR_$_{item}")
+                        else:
+                            symbols.add(item)
+            reexports = set()
+            for block in re.findall(r"reexported-libraries:.*?libraries:\s*\[([^\]]*)\]", doc, re.S):
+                reexports.update(x.strip().strip("'\"") for x in block.split(",") if x.strip())
+            yield name.group(1), symbols, reexports
+
+
+def main():
+    binary = sys.argv[1]
+    libs = {}
+    for name, symbols, reexports in tbd_documents():
+        entry = libs.setdefault(name, [set(), set()])
+        entry[0] |= symbols
+        entry[1] |= reexports
+
+    def resolves(install, symbol, seen=()):
+        if install not in libs or install in seen:
+            return False
+        symbols, reexports = libs[install]
+        return symbol in symbols or any(resolves(r, symbol, seen + (install,)) for r in reexports)
+
+    def ios_path(mac_path):
+        if mac_path in libs:  # e.g. IOKit keeps its Versions/A install name on iOS
+            return mac_path
+        m = re.match(r"/System/Library/Frameworks/(\w+)\.framework/", mac_path)
+        if m:
+            return f"/System/Library/Frameworks/{m.group(1)}.framework/{m.group(1)}"
+        return mac_path
+
+    loads = re.findall(r"cmd LC_LOAD(?:_WEAK)?_DYLIB\n\s+cmdsize \d+\n\s+name (\S+)",
+                       subprocess.check_output(["otool", "-l", binary], text=True))
+    short = {Path(p).name.replace(".dylib", "").split(".")[0]: p for p in loads}
+    undef = subprocess.check_output(["nm", "-m", "-u", binary], text=True)
+    report = {}
+    for line in undef.splitlines():
+        m = re.search(r"external (\S+) \(from (\S+)\)", line)
+        if not m:
+            continue
+        symbol, lib = m.groups()
+        mac = short.get(lib)
+        target = ios_path(mac) if mac else None
+        status = "resolved" if target and resolves(target, symbol) else "missing"
+        lib_report = report.setdefault(lib, {"mac_path": mac, "ios_path": target,
+                                             "ios_library_exists": target in libs,
+                                             "resolved": 0, "missing": []})
+        if status == "resolved":
+            lib_report["resolved"] += 1
+        else:
+            lib_report["missing"].append(symbol)
+    for lib, r in sorted(report.items(), key=lambda kv: -len(kv[1]["missing"])):
+        print(f"{lib:20} exists={r['ios_library_exists']!s:5} resolved={r['resolved']:4} missing={len(r['missing']):3} "
+              + " ".join(r["missing"][:12]) + (" ..." if len(r["missing"]) > 12 else ""))
+    if "--json" in sys.argv:
+        Path(sys.argv[sys.argv.index("--json") + 1]).write_text(json.dumps(report, indent=2) + "\n")
+
+
+if __name__ == "__main__":
+    main()