tools/third_party: add DENO_GN_PATH and DENO_NINJA_PATH env vars

tools/third_party.py

@@ -24,9 +24,16 @@ third_party_path = tp()
 depot_tools_path = tp("depot_tools")
 rust_crates_path = tp("rust_crates")
 python_packages_path = tp("python_packages")
-gn_path = tp(depot_tools_path, "gn")
 clang_format_path = tp(depot_tools_path, "clang-format")
-ninja_path = tp(depot_tools_path, "ninja")
+
+if "DENO_GN_PATH" in os.environ:
+    gn_path = os.environ["DENO_GN_PATH"]
+else:
+    gn_path = tp(depot_tools_path, "gn")
+if "DENO_NINJA_PATH" in os.environ:
+    ninja_path = os.environ["DENO_NINJA_PATH"]
+else:
+    ninja_path = tp(depot_tools_path, "ninja")
 
 python_site_env = None
 

website/manual.md

@@ -205,10 +205,16 @@ Extra steps for Windows users:
 
 # Update third_party modules
 git submodule update
+
+# Skip downloading binary build tools and point the build
+# to the system provided ones (for packagers of deno ...).
+./tools/setup.py --no-binary-download
+export DENO_BUILD_ARGS="clang_base_path=/usr clang_use_chrome_plugins=false"
+DENO_GN_PATH=/usr/bin/gn DENO_NINJA_PATH=/usr/bin/ninja ./tools/build.py
 ```
 
 Environment variables: `DENO_BUILD_MODE`, `DENO_BUILD_PATH`, `DENO_BUILD_ARGS`,
-`DENO_DIR`.
+`DENO_DIR`, `DENO_GN_PATH`, `DENO_NINJA_PATH`.
 
 ## API reference