The change in commit 27252b24 (cmComputeLinkInformation: Simplify
generator object access, 2015-08-02) broke the conditional use of a
target introduced in commit 41abdc17 (cmGeneratorTarget: Move GetSOName
from cmTarget, 2015-08-04). Restore the conditional lookup. Add a test
case that hacks platform information variables to trigger this code
everywhere.
Since commit v3.3.0-rc1~62^2~5 (cmTarget: Store only cmListFileContext
for CMP0023 handling, 2015-05-18) a call to target_link_libraries on a
target that was defined in another (non-ancestor) directory crashes
because no execution context is left active. Fix this by getting the
execution context from the actual cmMakefile where the current
target_link_libraries call takes place. Test this by verifying that
such calls correctly produce an error diagnostic instead of crashing.
Set the minimum required version of CMake high enough to avoid the
warning for CMAKE_LEGACY_CYGWIN_WIN32. The warning appears on stderr
and breaks the expected output matching.
Add a new signature to help populate INTERFACE_LINK_LIBRARIES and
LINK_LIBRARIES cleanly in a single call. Add policy CMP0023 to control
whether the keyword signatures can be mixed with uses of the plain
signatures on the same target.