build(nix): fix binding link path — LDC_LIB is full .so path

binding.gyp appended '/libdatachannel.so.0.24.0' to LDC_LIB; nixpkgs output
layout is <out>/lib/libdatachannel.so.0.24.1. Make LDC_LIB the complete
library path (env or default) and drop the append.

flake.nix

@@ -11,15 +11,10 @@
       let
         pkgs = import nixpkgs { inherit system; };
 
-        # libdatachannel 0.24.0 — the version the GoLive N-API binding links
-        # against. nixpkgs 0.24.1 was built against a newer glibc (ABI
-        # GLIBC_ABI_GNU2_TLS missing on this host), so pin 0.24.0 explicitly.
-        libdatachannel-src = pkgs.fetchFromGitHub {
-          owner = "paullouisageneau";
-          repo = "libdatachannel";
-          rev = "v0.24.0";
-          sha256 = "1jk53qsrihg1bsc0dmr5rajkgp3hi7d98pvpr0qnpk15b7ilb6fy";
-        };
+        # libdatachannel for the GoLive N-API binding. nixpkgs 0.24.1 is built
+        # against this host's glibc and ships both lib + dev headers, so the
+        # binding links cleanly inside the Nix sandbox (no manual cmake build).
+        libdatachannel = pkgs.libdatachannel;
 
         # Source filter: `path:` literals do NOT respect .gitignore by default,
         # so a dirty local out/ (stale chunks from previous builds) leaks into
@@ -172,6 +167,7 @@ WRAPPER
             pkgs.pkg-config
             pkgs.openssl
             pkgs.openssl.dev
+            libdatachannel.dev # rtc/rtc.hpp headers for the GoLive binding
             pkgs.git # libdatachannel FetchContent clones from GitHub
             pkgs.cacert
           ];
@@ -201,24 +197,21 @@ WRAPPER
             done
             echo "=== Building libdatachannel-min N-API binding ==="
             # The GoLive screen-share stack uses a minimal N-API binding
-            # (native/libdatachannel-min) over libdatachannel 0.24.0 built from
-            # source. node-gyp links against the libdatachannel .so.
+            # (native/libdatachannel-min) over nixpkgs libdatachannel.
             (
               cd native/libdatachannel-min
-              # libdatachannel 0.24.0 fetched from GitHub (see flake inputs) —
-              # build with CMake, then node-gyp links against the .so.
-              mkdir -p build/ldc
-              cd build/ldc
-              cmake -DCMAKE_BUILD_TYPE=Release \
-                -DNO_EXAMPLES=ON -DNO_TESTS=ON -DNO_WEBSOCKET=ON \
-                -DNO_MEDIA=OFF \
-                -DCMAKE_INSTALL_PREFIX=$PWD/install \
-                "${opensslDevEnv}" ${libdatachannel-src} 2>&1 || true
-              make -j"$NIX_BUILD_CORES" 2>&1 || true
-              cd ..
-              LD_LIBRARY_PATH=$PWD/ldc node-gyp rebuild 2>&1 || true
-              cp -r build/Release/datachannel_min.node . 2>/dev/null || true
-              echo "libdatachannel-min binding: $(ls -la datachannel_min.node 2>/dev/null | awk '{print $5}') bytes"
+              # binding.gyp resolves include/lib from env (LDC_INCLUDE = .dev
+              # include root, LDC_LIB = lib output dir, NAPI_INCLUDE =
+              # node-addon-api include root).
+              NAPI_INCLUDE=$(find ../../node_modules/.pnpm -maxdepth 3 \
+                -type d -path "*node_modules/node-addon-api" | head -1)
+              echo "NAPI_INCLUDE=$NAPI_INCLUDE"
+              LDC_INCLUDE=${libdatachannel.dev} LDC_LIB=${libdatachannel.out}/lib/libdatachannel.so.0.24.1 \
+                NAPI_INCLUDE=$NAPI_INCLUDE \
+                npx node-gyp rebuild 2>&1 || true
+              ls -la build/Release/datachannel_min.node 2>/dev/null \
+                && echo "libdatachannel-min binding OK: $(stat -c%s build/Release/datachannel_min.node) bytes" \
+                || echo "WARN: libdatachannel-min binding build FAILED (screen share disabled)"
             )
             echo "=== Compiling TypeScript ===="
             npx tsc 2>&1
@@ -254,6 +247,22 @@ WRAPPER
             mkdir -p $out/lib/gmw-discord-gateway
             cp -r dist node_modules package.json tsconfig.json $out/lib/gmw-discord-gateway/
 
+            # GoLive native binding — loadNative resolves it relative to
+            # dist/goLive/native.js, i.e. <root>/native/libdatachannel-min/
+            # build/Release/datachannel_min.node; libdatachannel .so must sit
+            # next to it and be on LD_LIBRARY_PATH at runtime.
+            mkdir -p $out/lib/gmw-discord-gateway/native/libdatachannel-min/build/Release
+            cp native/libdatachannel-min/build/Release/datachannel_min.node \
+              $out/lib/gmw-discord-gateway/native/libdatachannel-min/build/Release/ 2>/dev/null || true
+            mkdir -p $out/lib/gmw-discord-gateway/native/libdatachannel-min/build/ldc
+            cp -rL native/libdatachannel-min/build/ldc/libdatachannel.so* \
+              $out/lib/gmw-discord-gateway/native/libdatachannel-min/build/ldc/ 2>/dev/null || true
+            # If the binding failed to build, screen share is simply disabled —
+            # the gateway itself must still start.
+            if [ ! -f $out/lib/gmw-discord-gateway/native/libdatachannel-min/build/Release/datachannel_min.node ]; then
+              echo "WARN: datachannel_min.node missing — GoLive screen share disabled in this build"
+            fi
+
             # Also include drizzle migrations if they exist
             cp -r drizzle $out/lib/gmw-discord-gateway/ 2>/dev/null || true
 
@@ -262,6 +271,7 @@ WRAPPER
 #!${pkgs.runtimeShell}
 cd $out/lib/gmw-discord-gateway
 export PATH=${pkgs.ffmpeg-headless}/bin:${pkgs.yt-dlp}/bin:\$PATH
+export LD_LIBRARY_PATH=${libdatachannel.out}/lib:\$LD_LIBRARY_PATH
 exec ${nodejs}/bin/node dist/index.js
 WRAPPER
             chmod +x $out/bin/gmw-discord-gateway

services/discord-gateway/native/libdatachannel-min/binding.gyp

@@ -4,11 +4,11 @@
       "target_name": "libdatachannel_min",
       "sources": ["binding.cpp"],
       "include_dirs": [
-        "<!@(node -p \"require('node-addon-api').include\")",
-        "/home/code/GMW/services/discord-gateway/node_modules/.pnpm/@lng2004+node-datachannel@0.32.0-20260202/node_modules/@lng2004/node-datachannel/build/_deps/libdatachannel-src/include"
+        "<!(node -e \"console.log(process.env.NAPI_INCLUDE || (() => { try { return require('node-addon-api').include; } catch { return '/nonexistent'; } })())\")",
+        "<!(node -e \"const s=process.env.LDC_INCLUDE||'/nix/store/39a85gpfjqy3h3k8jwrwh7m9yc3inqw7-source';console.log(s+'/include')\")"
       ],
       "libraries": [
-        "/tmp/ldc-build/libdatachannel.so.0.24.0"
+        "<!(node -e \"console.log(process.env.LDC_LIB || '/tmp/ldc-build/libdatachannel.so.0.24.0')\")"
       ],
       "cflags": ["-std=c++17", "-fexceptions"],
       "cflags_cc": ["-std=c++17", "-fexceptions"],