Build failure with CMake 4

[AdrianBunk]

https://bugs.debian.org/1113326

CMake Error at CMakeLists.txt:1 (CMAKE_MINIMUM_REQUIRED):
  Compatibility with CMake < 3.5 has been removed from CMake.

Just bumping it to 3.5 fails due to the next line:

CMake Error at CMakeLists.txt:2 (cmake_policy):
  Policy CMP0043 may not be set to OLD behavior because this version of CMake
  no longer supports it.  The policy was introduced in CMake version 3.0.0,
  and use of NEW behavior is now required.

  Please either update your CMakeLists.txt files to conform to the new
  behavior or use an older version of CMake that still supports the old
  behavior.  Run cmake --help-policy CMP0043 for more information.