Clang symlink failure

Clean install on windows WSL Ubuntu image following https://emscripten.org/docs/getting_started/downloads.html and then running `emcc` results in:
```
nn@DESKTOP-TTT:/mnt/c/Data/Desktop/wasm-test$ emcc
emcc: error: '/mnt/c/Data/Desktop/wasm-test/emsdk/upstream/bin/clang --version' failed: [Errno 8] Exec format error: '/mnt/c/Data/Desktop/wasm-test/emsdk/upstream/bin/clang'
```
`upstream/bin/clang` was an empty file:
```
nn@DESKTOP-TTT:/mnt/c/Data/Desktop/wasm-test/emsdk$ file ./upstream/bin/clang
./upstream/bin/clang: empty
```
creating symlink of `clang` to `clang-15` fixed it, the exact line was:
```
ln -s clang-15 clang
```

/mnt/c is drvfs:
```
C:\ on /mnt/c type drvfs (rw,noatime,uid=1000,gid=1000,case=off)
```

WSL version is 1:
```
NAME STATE VERSION
* Ubuntu-20.04 Running 1
```