We can do this check only if the TargetName is non-empty, which means
that we're evaluating INTERFACE_INCLUDE_DIRECTORIES from a linked
dependency which was set using target_link_libraries.
It is possible to have relative paths in INCLUDE_DIRECTORIES already
in CMake 2.8.10.2, so that part will require a policy to fix.
It is considered an error if the INTERFACE_INCLUDE_DIRECTORIES contains
a directory which does not exist, which indicates a programmer error
by the upstream, or a packaging error.
One of the RunCMake.CompatibleInterface tests also needs to be updated
due to this change. Non-existant includes were used in the test, but
are not needed.
Check that source and binary directories are not part of the
INTERFACE_INCLUDE_DIRECTORIES for installed IMPORTED targets.
This is limited to directories which do not contain generator
expressions to evaluate. Such paths can only be checked at time
of use of the imported target, which will be done in a follow up
patch.
This fixes a regression introduced in commit 290e92ad (Move
GetIncludeDirectories to cmGeneratorTarget, 2012-09-16) which loops over
cmGeneratorTargets before they get created, so the container is empty.
Stephen Kelly