Index: lib/scudo/standalone/CMakeLists.txt
===================================================================
--- lib/scudo/standalone/CMakeLists.txt
+++ lib/scudo/standalone/CMakeLists.txt
@@ -9,6 +9,10 @@
   -Werror
   -nostdinc++)
 
+# Do not error out on spurious flags. They can be passed via CMAKE_CXX_FLAGS
+# for example, so we have very little control on those.
+list(APPEND SCUDO_CFLAGS -Wno-unused-command-line-argument)
+
 append_list_if(COMPILER_RT_HAS_FFREESTANDING_FLAG -ffreestanding SCUDO_CFLAGS)
 
 append_list_if(COMPILER_RT_HAS_FVISIBILITY_HIDDEN_FLAG -fvisibility=hidden SCUDO_CFLAGS)