Error on relative include with generator expression.
Diagnostics in CMake 2.8.12 and lower silently ignored an entry in the
INTERFACE_INCLUDE_DIRECTORIES of a target if it contained a generator
expression at any position.
The path entries in that target property should not be relative. High-level API should ensure that by adding either a source directory or a install directory prefix, as appropriate.
OLD behavior for this policy is to ignore relative path entries if they
contain a generator expression. The
NEW behavior for this policy is to report
an error if a generator expression appears in another location and the path is
This policy was introduced in CMake version 3.0. CMake version
3.21.20210805-g371d5c7 warns when the policy is not set and uses
OLD behavior. Use
cmake_policy() command to set it to
OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.