VS: Fix support for '/guard:cf' linker flag
This commit restores a previous commit, 82a5c2c6 (VS: Fix support for '/guard:cf' linker flag, 2017-06-30), which was removed during an earlier refactoring.
The entry for LinkControlFlowGuard
in v143_Link.json does not work
when used in a .vcxproj
file. Drop our link flag table entries for
this toolset so that the flag will be passed via AdditionalOptions
.