[llvm] [cmake] Allow multiple LibEdit_LIBRARIES (PR #93896)

[Daniel Thornburgh via llvm-commits]

mysterymath wrote:

> In my case with a statically linked libedit (& ncurses/libtinfo) pkg-config (in static mode, with `--static`) is aware of the `-ltinfo` dependency. I was able to make my build work, without forcing `LibEdit_LIBRARIES` to any value, with a patch like this:
> 
> ```
> Author: Romain Geissler <romain.geissler at amadeus.com>
> Date:   Tue Aug 13 02:22:31 2024 +0000
>     
>     Use include and libraries from libedit's pkg-config, which can be a list.
> 
> diff --git a/llvm/cmake/modules/FindLibEdit.cmake b/llvm/cmake/modules/FindLibEdit.cmake
> index b3f49e1477f0..06266d05a24d 100644
> --- a/llvm/cmake/modules/FindLibEdit.cmake
> +++ b/llvm/cmake/modules/FindLibEdit.cmake
> @@ -54,12 +54,16 @@ find_package_handle_standard_args(LibEdit
>                                    REQUIRED_VARS
>                                      LibEdit_INCLUDE_DIRS
>                                      LibEdit_LIBRARIES
> +                                    PC_LIBEDIT_LIBRARIES
> +                                    PC_LIBEDIT_LIBDIR
> +                                    PC_LIBEDIT_INCLUDE_DIRS
>                                    VERSION_VAR
>                                      LibEdit_VERSION_STRING)
>  mark_as_advanced(LibEdit_INCLUDE_DIRS LibEdit_LIBRARIES)
> 
>  if (LibEdit_FOUND AND NOT TARGET LibEdit::LibEdit)
>    add_library(LibEdit::LibEdit INTERFACE IMPORTED)
> -  target_link_libraries(LibEdit::LibEdit INTERFACE ${LibEdit_LIBRARIES})
> -  target_include_directories(LibEdit::LibEdit INTERFACE ${LibEdit_INCLUDE_DIRS})
> +  target_link_libraries(LibEdit::LibEdit INTERFACE ${PC_LIBEDIT_LIBRARIES})
> +  target_link_directories(LibEdit::LibEdit INTERFACE ${PC_LIBEDIT_LIBDIR})
> +  target_include_directories(LibEdit::LibEdit INTERFACE ${PC_LIBEDIT_INCLUDE_DIRS})
>  endif()
> ```
> 
> However if I understand correctly your usage (forcing manually `LibEdit_LIBRARIES`) it would break you if something like was merged. I wonder what to do here (I don't really like the idea of manually providing `LibEdit_LIBRARIES` myself while it seems at least in some cases pkg-config is good enough to find the necessary libraries.

Would it be possible to set `LibEdit_LIBRARIES` using the information from pkg-config?

https://github.com/llvm/llvm-project/pull/93896