Make things build on i386-gnu again

[bugaevc]

cc:

• @spholz and @BertalanD for the LibELF change
• @nico for LibPDF & JBIG2
• @ADKaster for Core::MachPort
• @stelar7 for LibCrypto / MGF

[bugaevc]

Visual proof that things still work:

[bugaevc]

Error: An error occurred trying to start process '/usr/bin/bash' with working directory '/home/runner/work/serenity/serenity/Build/x86_64'. No such file or directory

That's clearly not my fault?

[bugaevc]

Pushed a fix for aarch64-gnu.

By the way, please feel free to cherry-pick individual patches, they should be independent from each other.

[DanShaders]

I think LibELF changes are not required anymore after (merged) #24105. We don't build these files on lagom now.

[bugaevc]

I think LibELF changes are not required anymore after (merged) #24105. We don't build these files on lagom now.

It built fine without the ELF changes indeed, thanks!