libffi: 3.2 is also broken for 64-bit; use frida version

[nirbheek]

Seems ARM64 libffi is still broken when used with Bowser, so let's use frida's
libffi which they say works on multiple platforms

EricssonResearch/openwebrtc#177 (comment)

[nirbheek]

While testing, you'll want to do rm -rf ~/cerbero/dist/android_armv7/lib/libffi-3.2.1/ to get rid of the old headers (although the pkg-config file has the updated path, so in theory this shouldn't be needed)

[Rugvip]

Let's use the a fixed commit here as well: 4e2166049f897a904e4c3ce367e4e8ddb54e0ad0

[nirbheek]

I hesitated with that because there was no clear way to ensure that the commit id would be chosen from the "frida" remote, and not "origin".

[Rugvip]

That's fine, if origin has an identical commit we might as well use that one :D

[nirbheek]

But the older commits in that sequence of commits might be different!

[sdroege]

The commit id changes if the history to that commit changes

[nirbheek]

Comments should be addressed now. :)