The following was disallowed:
add_library(iface INTERFACE)
target_link_libraries(iface PUBLIC)
just due to the mention of the `PUBLIC` keyword. Instead, only error if
there are actually `PUBLIC` dependencies specified (and analogously for
other restrictions).
Update tests to expect this new behavior.
Not all of these commands accept non-compilable (i.e., IMPORTED)
targets, so those calls are currently just commented out. If they ever
do start to accept them, the tests should be enabled.
This family enable to manage link flags
Three new properties:
* directory property: LINK_OPTIONS
* target properties: LINK_OPTIONS and INTERFACE_LINK_OPTIONS
Two new commands
* add_link_options(): to populate directory property
* target_link_options(): to populate target properties
Fixes: #16543
Ben Boeckel