The result is that the depends of the target are created.
So,
add_library(somelib foo.cpp)
add_library(anotherlib EXCLUDE_FROM_ALL foo.cpp)
add_library(extra EXCLUDE_FROM_ALL foo.cpp)
target_link_libraries(anotherlib extra)
add_library(iface INTERFACE)
target_link_libraries(iface INTERFACE anotherlib)
Executing 'make iface' will result in the anotherlib and extra targets
being made.
Adding a regular executable to the INTERFACE of an INTERFACE_LIBRARY
will not result in the executable being built with 'make iface' because
of the logic in cmComputeTargetDepends::AddTargetDepend.
So far, this is implemented only for the Makefile generator. Other
generators will follow if this feature is possible for them.
Make INTERFACE_LIBRARY targets part of the all target by default.
Test this by building the all target and making the expected library
EXCLUDE_FROM_ALL.