[libunwind] Removes CMake work-arounds.

CMake older than 3.20.0 is no longer supported.
This removes work-arounds for no longer supported versions.

Reviewed By: #libunwind, mstorsjo

Differential Revision: https://reviews.llvm.org/D152100

GitOrigin-RevId: 17b0d90e20eed93bd55a57c614565e7c9fbae3b1
1 file changed
tree: 24e8717a188677f1bd0ffe66b62b9ed2cbf14020
  1. cmake/
  2. docs/
  3. include/
  4. src/
  5. test/
  6. .clang-format
  7. CMakeLists.txt
  8. LICENSE.TXT