libarchive: Avoid requiring CMake 2.8.8 for CMakeExpandImportedTargets

Drop the custom versions of CheckCSourceCompiles/CheckCSourceRuns
because we do not use the SAFESEH option anyway.
Merge topic 'update-libarchive' into next

d77cfca libarchive: Avoid requiring CMake 2.8.8 for CMakeExpandImportedTargets