fix windows clang compilation for ffi

[AndreyMlashkin]

Specify library name and version: libffi/3.4.2@

This is also a good place to share with all of us why you are submitting this PR (specially if it is a new addition to ConanCenter): is it a dependency of other libraries you want to package? Are you the author of the library? Thanks!

closes: #9954

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• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[SSE4]

I hope it doesn't break MinGW, Intel, whatever else may run on Windows

[AndreyMlashkin]

I hope it doesn't break MinGW, Intel, whatever else may run on Windows

adding m64 was ignored for clang and it will be also ignored for mingw :)

[AndreyMlashkin]

How to restart the build?

[uilianries]

How to restart the build?

You just did it. close/open the PR works too.

[SpaceIm]

this approach seems neater: #9993

[conan-center-bot]

All green in build 8 (209d84f22fb3a69dd57e4ab5b8fe1549aea500c6):

• libffi/3.2.1@:
  All packages built successfully! (All logs)

• libffi/3.3@:
  All packages built successfully! (All logs)

• libffi/3.4.2@:
  All packages built successfully! (All logs)