[libclc] [libclc] Remove unused and incorrect pkgconf file (PR #185654)

[Nikita Popov via cfe-commits]

nikic wrote:

Isn't this how mesa finds libclc? https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/compiler/clc/meson.build?ref_type=heads#L44

This pkgconfig file *used* to work correctly, but it seems like there were a bunch of changes (moving libclc into the clang resource directory, using per-target directories) that broke it.

I'm not sure what the correct way for mesa to find libclc is supposed to be now.

https://github.com/llvm/llvm-project/pull/185654