Commit 650e61f8 (Add a convenient way to add the includes install
dir to the INTERFACE., 2013-01-05) introduced an error case for
using the install(TARGETS) command with specified INCLUDES DESTINATION,
but no specified EXPORT set.
It is convenient to use a variable to set the various destinations
for different outputs (as KDE does), and some targets such as
executables are installed but not exported. This was triggering
the error case, but as it is a common case, remove the error.
Export the INCLUDES DESTINATION without appending to the
INTERFACE_INCLUDE_DIRECTORIES of the target itself. That way, a target
can be exported multiple times with different INCLUDES DESTINATION
without unintended cross-pollution of export sets.
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