Fix: Work around cmake bug by stripping link target strings

cmake/LinkPackage.cmake

@@ -4,10 +4,15 @@ function(link_package NAME)
     if(${NAME}_FOUND)
         string(TOUPPER "${NAME}" UCNAME)
         add_definitions(-DWITH_${UCNAME})
+        # Some libraries' cmake packages (looking at you, SDL2) leave trailing whitespace in the link commands,
+        # which (later) cmake considers to be an error. Work around this with by stripping the incoming string.
         if(LP_TARGET AND TARGET ${LP_TARGET})
+            string(STRIP "${LP_TARGET}" LP_TARGET)
             target_link_libraries(openttd ${LP_TARGET})
             message(STATUS "${NAME} found -- -DWITH_${UCNAME} -- ${LP_TARGET}")
         else()
+            string(STRIP "${${NAME}_LIBRARY}" ${NAME}_LIBRARY)
+            string(STRIP "${${NAME}_LIBRARIES}" ${NAME}_LIBRARIES)
             include_directories(${${NAME}_INCLUDE_DIRS} ${${NAME}_INCLUDE_DIR})
             target_link_libraries(openttd ${${NAME}_LIBRARIES} ${${NAME}_LIBRARY})
             message(STATUS "${NAME} found -- -DWITH_${UCNAME} -- ${${NAME}_INCLUDE_DIRS} ${${NAME}_INCLUDE_DIR} -- ${${NAME}_LIBRARIES} ${${NAME}_LIBRARY}")