Update zstd cmake usage to the provided by the upstream

[uilianries]

Hello! The project Zstd does not have an official cmake config file, neither find cmake available in the official cmake modules.

However, the project itself offers cmake support, including a config file and targets:

https://github.com/facebook/zstd/blob/dev/build/cmake/zstdConfig.cmake

https://github.com/facebook/zstd/blob/dev/build/cmake/CMakeLists.txt#L181

So, consuming zstd would be:

find_package(zstd CONFIG REQUIRED)

...

target_link_libraries(dwarf PRIVATE $<TARGET_EXISTS:zstd::libzstd_static>,zstd::libzstd_static,zstd::libzstd_shared>)

This would follow the correct way, following the current zstd project. In order to have effect, it would need to update libdwarf-code CMakeLists.txt, and FindZTD.cmake in this project, to follow the expect names.

In case you are inclined to accept the idea, I could open a PR with the fix.

[davea42]

I hope @jeremy-rifkin and @flagarde will have comments on this.

I think it seems like a fine idea and a pull request would be good. Thanks!

[uilianries]

Having a second, part of this issue is implemented already: https://github.com/davea42/libdwarf-code/blob/main/CMakeLists.txt#L211

The only thing would be renaming the package to zstd instead of the current one ZSTD (all upper-case)

[davea42]

Of course you do not mean to replace all 599 ZSTD with zstd, but I am not at all sure which instances need changing.

[uilianries]

@davea42 Sorry, I meant https://github.com/davea42/libdwarf-code/blob/main/CMakeLists.txt#L203 to use zstd, like:

find_package(zstd)