FindLibEdit uses pkg-config to find the necessary flags, but this may break with cross-compilation,
because the PkgConfig module in CMake doesn't respect the SYSROOT specified in a toolchain file.
Instead of taking the parameters from pkg-config for granted, we check whether our compiler can
actually include and link against the library.
Fixes#55445Fixes#55671
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D126450
Currently, LLVM's LineEditor and LLDB both use libedit, but find them in different (inconsistent) ways.
This causes issues e.g. when you are using a locally installed version of libedit, which will not be used
by clang-query, but by lldb if picked up by FindLibEdit.cmake
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D124673
Tobias Ribizel