emsdk install sdk-main-64bit no longer works.

[juj]

A fresh install of Emsdk from source no longer works on Windows:

git clone https://emscripten-core/emsdk.git
cd emsdk
emsdk install sdk-main-64bit

fails in

...
Resolving deltas: 100% (146893/146893), done.
Updating files: 100% (9514/9514), done.
Submodule 'test/third_party/googletest' (https://github.com/google/googletest) registered for path 'test/third_party/googletest'
Submodule 'test/third_party/posixtestsuite' (https://github.com/emscripten-core/posixtestsuite) registered for path 'test/third_party/posixtestsuite'
Submodule 'test/third_party/wasi-test-suite' (https://github.com/khronosproject/wasi-test-suite) registered for path 'test/third_party/wasi-test-suite'
Cloning into 'C:/emsd2/emscripten/main/test/third_party/googletest'...
remote: Enumerating objects: 27977, done.
remote: Counting objects: 100% (230/230), done.
remote: Compressing objects: 100% (143/143), done.
remote: Total 27977 (delta 148), reused 88 (delta 87), pack-reused 27747 (from 2)
Receiving objects: 100% (27977/27977), 13.47 MiB | 18.29 MiB/s, done.
Resolving deltas: 100% (20737/20737), done.
Cloning into 'C:/emsd2/emscripten/main/test/third_party/posixtestsuite'...
remote: Enumerating objects: 3626, done.
remote: Counting objects: 100% (126/126), done.
remote: Compressing objects: 100% (74/74), done.
remote: Total 3626 (delta 64), reused 101 (delta 52), pack-reused 3500 (from 1)
Receiving objects: 100% (3626/3626), 1.94 MiB | 8.95 MiB/s, done.
Resolving deltas: 100% (1534/1534), done.
Cloning into 'C:/emsd2/emscripten/main/test/third_party/wasi-test-suite'...
remote: Enumerating objects: 427, done.
remote: Counting objects: 100% (25/25), done.
remote: Compressing objects: 100% (11/11), done.
remote: Total 427 (delta 17), reused 14 (delta 14), pack-reused 402 (from 1)
Receiving objects: 100% (427/427), 11.17 MiB | 19.62 MiB/s, done.
Resolving deltas: 100% (295/295), done.
Submodule path 'test/third_party/googletest': checked out 'b514bdc898e2951020cbdca1304b75f5950d1f59'
Submodule path 'test/third_party/posixtestsuite': checked out '869e266b090a8d44e51bb040904c942556b1e4ab'
Submodule path 'test/third_party/wasi-test-suite': checked out 'ac9371207fc61972a21d7d086074ca690a99d14d'
Running post-install step: npm ci ...
Running post-install step: npm install google-closure-compiler-windows@20240317.0.0
Removed google-closure-compiler-java dependency.
Done running: npm ci
Error running ['C:\\Python311\\python.exe', 'C:/emsd2/emscripten/main\\bootstrap.py']:
bootstrap: warning: config file not found: C:\emsd2\emscripten\main\.emscripten.  You can create one by hand or run `emcc --generate-config`
bootstrap: error: LLVM_ROOT not set in config (C:\emsd2\emscripten\main\.emscripten), and `clang` not found in PATH

error: installation failed!

Running emcc --generate-config in Emscripten root directory does work around the issue, although does leak linux-isms on Windows:

C:\emsd2\emscripten\main>emcc --generate-config
An Emscripten settings file has been generated at:

  C:\emsd2\emscripten\main\.emscripten

It contains our best guesses for the important paths, which are:

  LLVM_ROOT       = /usr/bin
  BINARYEN_ROOT   = /usr/local
  NODE_JS         = C:\Program Files\nodejs\node.EXE

Please edit the file if any of those are incorrect.

After running emcc --generate-config, returning to the sdk main install works. I.e.

git clone https://emscripten-core/emsdk.git
cd emsdk
emsdk install sdk-main-64bit
pushd emscripten\main
emcc --generate-config
popd
emsdk install sdk-main-64bit

works around the issue.