fix the Windows build

Summary:
It looks like I also broke the Windows build of folly in D10435249, since
FollyCompilerMSVC.cmake referenced the `folly_deps` target, which is now not
defined yet when `FollyCompilerMSVC.cmake` is included.

This changes the code so that `FollyCompilerMSVC.cmake` simply updates
`${FOLLY_LINK_LIBRARIES}`, which is used in a `target_link_libraries()` call
in `folly-deps.cmake`.  (I'm slightly surprised that CMake was happy before
with multiple separate `target_link_libraries()` calls for the `folly_deps`
target.)

Reviewed By: Orvid

Differential Revision: D10445483

fbshipit-source-id: 5277785bec3fd8527d01a098e130c945077703ee

CMake/FollyCompilerMSVC.cmake

@@ -295,8 +295,4 @@ function(apply_folly_compile_options_to_target THETARGET)
   endif()
 endfunction()
 
-target_link_libraries(folly_deps
-  INTERFACE
-    Iphlpapi.lib
-    Ws2_32.lib
-)
+list(APPEND FOLLY_LINK_LIBRARIES Iphlpapi.lib Ws2_32.lib)