See https://trac.macports.org/ticket/62706

--- DAEValidator/CMakeLists.txt.orig	2018-11-26 15:43:10.000000000 -0700
+++ DAEValidator/CMakeLists.txt	2021-04-17 15:05:56.000000000 -0700
@@ -100,7 +100,7 @@
 # C4820: 'bytes' bytes padding added after construct 'member_name'
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP /Wall /WX /wd4505 /wd4514 /wd4592 /wd4710 /wd4711 /wd4820")
 else ()
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Werror")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall")
 endif ()
 
 add_custom_command(