add doc for building for web

flake.nix

@@ -58,6 +58,7 @@
               # Zig / webAssembly impl.
               zig
               zls
+              emscripten
             ];
 
             # see: https://discourse.nixos.org/t/flutter-run-d-linux-build-process-failed/16552/2

zig/README.md

@@ -0,0 +1,11 @@
+# FabApp
+
+## Build for web
+
+- https://github.com/ryupold/examples-raylib.zig
+    * https://github.com/ryupold/examples-raylib.zig/blob/main/build.zig
+- https://github.com/ziglang/zig/issues/10836#issuecomment-1666488896
+- https://github.com/ziglang/zig/pull/17210
+    * https://github.com/mitchellh/zig-overlay 
+- https://github.com/bluesillybeard/ZigAndRaylibSetup
+- https://github.com/nrdmn/awesome-zig#web

zig/justfile

@@ -6,6 +6,10 @@ alias fmt := format
 build:
     zig build
 
+web-build:
+     # zig build-lib src/main.zig -target wasm32-freestanding -dynamic -rdynamic
+     zig build -Dtarget=wasm32-emscripten --sysroot /nix/store/zll7a6ns3avx509kgx0jjghz8g89l2g0-emscripten-3.1.45
+
 run:
     nixGL zig build run