broken linking with libwebp-1.3.1

[vcunat]

libwebp 1.3.1 changed their .pc files: webmproject/libwebp@31c28db

and as a result chafa will fail, unless e.g. -lwebp flag is supplied manually.
Examples:

• libwebp: 1.3.0 -> 1.3.1 NixOS/nixpkgs#240893 (comment)
• https://bugs.gentoo.org/909429

[hpjansson]

Hey, thanks for reporting this! Seems like a quick fix, but I'm a bit device challenged today so it'll have to wait till I'm back in the bat cave; tomorrow or monday.

[vcunat]

No need to hurry, from my point of view. We fixup it in distro(s) like this for now, but I thought it would be nice to have a proper released fix at some point in future.