CMake warning about deprecated policy related to RPATH #1721
Description
CMake 3.11.2 warns:
CMake Deprecation Warning at CMakeLists.txt:4 (cmake_policy):
The OLD behavior for policy CMP0042 will be removed from a future version
of CMake.
The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
The triggering code was added in commit ac5fd3a with the intention:
Set CMake policy CMP0042
to remove the warning below when running cmake.
In the long run changing the CMake rules to set MACOSX_RPATH
might be the better option.
CMake Warning (dev):
Policy CMP0042 is not set: MACOSX_RPATH is enabled by default. Run "cmake
--help-policy CMP0042" for policy details. Use the cmake_policy
command to set the policy and suppress this warning.
MACOSX_RPATH is not specified for the following targets:
libledger
This warning is for project developers. Use -Wno-dev to suppress it.
Policy CMP0042 is (AFAIUI) irrelevant to Linux where CMake 3.11.2 seems to do Almost The Right Thing™ by default (set RPATH for ledger to source directory when building and testing and to (for example) /usr/lib64 when installing; some/most distributions will want to clear that field when installing by setting CMAKE_SKIP_INSTALL_RPATH). So my instinct would be to remove the four lines from CMakeLists.txt and the one line from src/CMakeLists.txt that relate to RPATH.
But I do not know how this plays out under macOS. I assume the default there is reasonable as well, but I have no way of testing this.