Add the missing include to fix an error when `cmake_push_check_state()`
is called and incidentally the CMakePushCheckState module is not loaded
by any other check running prior to `FindLibEdit.cmake`:
CMake Error at /var/no-tmpfs/portage/dev-util/lldb-15.0.4/work/cmake/Modules/FindLibEdit.cmake:24 (cmake_push_check_state):
Unknown CMake command "cmake_push_check_state".
Call Stack (most recent call first):
cmake/modules/LLDBConfig.cmake:52 (find_package)
cmake/modules/LLDBConfig.cmake:59 (add_optional_dependency)
CMakeLists.txt:28 (include)
Gentoo Bug: https://bugs.gentoo.org/880065
Differential Revision: https://reviews.llvm.org/D137555
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
