cmake: msgpack: Check all lib names per directory

By default, find_library() searches all directories for one possible
name and then looks for the next name.  To make sure we're building
against the same headers and libraries, look for all names in a
directory before moving to the next one.

cmake/FindMsgpack.cmake

@@ -43,6 +43,9 @@ endif()
 list(APPEND MSGPACK_NAMES msgpackc msgpack)
 
 find_library(MSGPACK_LIBRARY NAMES ${MSGPACK_NAMES}
+  # Check each directory for all names to avoid using headers/libraries from
+  # different places.
+  NAMES_PER_DIR
   HINTS ${PC_MSGPACK_LIBDIR} ${PC_MSGPACK_LIBRARY_DIRS}
   ${LIMIT_SEARCH})