[feature request] support emsdk and setup-emsdk (and maybe upstream this GitHub Action) on Alpine Linux as well

I'm getting this error message from emconfigure/configure/autotools on Alpine Linux (running within Docker on Ubuntu on Github Actions). On Ubuntu everything works fine.

The actual error from `config.log`: `emcc: error: '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/bin/clang --version' failed: [Errno 2] No such file or directory: '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/bin/clang'`

I'm installing Emscripten with https://github.com/mymindstorm/setup-emsdk:
```
Run mymindstorm/setup-emsdk@v10
with:
version: 2.0.30
no-install: false
no-cache: false
update-tags: false
env:
UBUNTUPACKAGES: texlive-latex-base texlive-latex-extra texlive-latex-recommended texlive-science
EMSCRIPTEN_VERSION: 2.0.30
MAKE_PARALLELISM: -j2
/usr/bin/docker exec 54062d2bc936a72370a8ed67205b8a68a46d5b896a3f3946eee643068dee3e2e sh -c "cat /etc/*release | grep ^ID"
/usr/bin/unzip -q /__w/_temp/0daf1bd6-8be8-4fd1-aa20-b002ea1b2006
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk update-tags
`update-tags` is not longer needed. To install the latest tot release just run `install tot`
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk install 2.0.30
Resolving SDK version '2.0.30' to 'sdk-releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'
Installing SDK 'sdk-releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'..
Installing tool 'node-14.15.5-64bit'..
Downloading: /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/zips/node-v14.15.5-linux-x64.tar.xz from https://storage.googleapis.com/webassembly/emscripten-releases-builds/deps/node-v14.15.5-linux-x64.tar.xz, 21391232 Bytes
[----------------------------------------------------------------------------]
Unpacking '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/zips/node-v14.15.5-linux-x64.tar.xz' to '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit'
Done installing tool 'node-14.15.5-64bit'.
Installing tool 'releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'..
Downloading: /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/zips/c69458f1bbf3ef5b8da4e934de210659cc9bca04-wasm-binaries.tbz2 from https://storage.googleapis.com/webassembly/emscripten-releases-builds/linux/c69458f1bbf3ef5b8da4e934de210659cc9bca04/wasm-binaries.tbz2, 252525504 Bytes
[----------------------------------------------------------------------------]
Unpacking '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/zips/c69458f1bbf3ef5b8da4e934de210659cc9bca04-wasm-binaries.tbz2' to '/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream'
Done installing tool 'releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'.
Done installing SDK 'sdk-releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'.
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk activate 2.0.30
Resolving SDK version '2.0.30' to 'sdk-releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit'
Setting the following tools as active:
node-14.15.5-64bit
releases-upstream-c69458f1bbf3ef5b8da4e934de210659cc9bca04-64bit

Next steps:
- To conveniently access emsdk tools from the command line,
consider adding the following directories to your PATH:
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/emscripten
- This can be done for the current shell by running:
source "/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk_env.sh"
- Configure emsdk in your shell startup scripts by running:
echo 'source "/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk_env.sh"' >> $HOME/.bash_profile
/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/emsdk construct_env
Adding directories to PATH:
PATH += /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main
PATH += /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/emscripten
PATH += /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin

Setting environment variables:
PATH = /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main:/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/emscripten:/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
EMSDK = /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main
EM_CONFIG = /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/.emscripten
EMSDK_NODE = /__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin/node
export PATH="/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main:/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/upstream/emscripten:/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
export EMSDK="/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main";
export EM_CONFIG="/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/.emscripten";
export EMSDK_NODE="/__w/_temp/d92e89d6-8eff-426f-84ac-b34bee205894/emsdk-main/node/14.15.5_64bit/bin/node";
```