Initial support for setjmp/longjmp for PHP v7.4.32

[fd]

This patch takes the setjmp polyfill from Ruby and integrates it with PHP v7.4.32.

Missing bits:

• running wasm-opt with the asyncify pass.
  wasm-opt -O --asyncify -g --pass-arg=asyncify-ignore-imports -o [OUTPUT] [INPUT]
• update READMEs
• integrate with other PHP versions
• maybe turn it into a lib so other dependencies can also use it

[vmwclabot]

@fd, you must sign our contributor license agreement before your changes are merged. Click here to sign the agreement. If you are a VMware employee, read this for further instruction.

[vmwclabot]

@fd, we have received your signed contributor license agreement. The review is usually completed within a week, but may take longer under certain circumstances. Another comment will be added to the pull request to notify you when the merge can proceed.

[assambar]

This is a great step forward.
We will definitely have to revise it more if we end up trying to merge this effort upstream into the PHP source base, but it is a huge improvement already!
There are some nits in the code, which again I will consider revisiting only later when we try going upstream.

[ereslibre]

Thank you @fd. This is a great contribution. Some comments from my side.

As for the TODO list, I think we can iterate on this. For other PHP versions, I would aim for the 8.1 and 8.2 versions.

[ereslibre]

I think it would be great to keep your authorship here :)

[ereslibre]

In order to do proper attribution, would you mind to update the patch with the information you prefer to be shown as your identity?

[ereslibre]

Suggested change

	cp sapi/cgi/php-cgi-asyncify ${WASMLABS_OUTPUT}/bin/php-cgi${WASMLABS_RUNTIME:+-$WASMLABS_RUNTIME} || exit 1
	mv sapi/cgi/php-cgi-asyncify ${WASMLABS_OUTPUT}/bin/php-cgi${WASMLABS_RUNTIME:+-$WASMLABS_RUNTIME} || exit 1

[vmwclabot]

@fd, VMware has approved your signed contributor license agreement.

[ereslibre]

Now after merging #33, this will need a rebase.

[ereslibre]

@fd: we are thinking in merging your code rebasing it on top of current main, fixing merging conflicts. Would that be fine for you?

[ereslibre]

Hello @fd,

Sorry for the long time to reply and thank you for your contribution. After some long discussions, this project is currently in the process of being archived. However, the development of this project will continue as an independent community fork present at https://github.com/webassemblylabs/webassembly-language-runtimes.

We would be grateful if you could recreate your contribution under that fork and we will work on applying it.