diff --git a/mk/platform.mk b/mk/platform.mk
index ba1cbc32f54..471ad667a2a 100644
--- a/mk/platform.mk
+++ b/mk/platform.mk
@@ -29,7 +29,7 @@ $(foreach t,$(CFG_TARGET_TRIPLES),$(info cfg: os for $(t) is $(OSTYPE_$(t))))
 # FIXME: no-omit-frame-pointer is just so that task_start_wrapper
 # has a frame pointer and the stack walker can understand it. Turning off
 # frame pointers everywhere is overkill
-CFG_GCCISH_CFLAGS += -fno-omit-frame-pointer
+CFG_GCCISH_CFLAGS += -fno-omit-frame-pointer -DUSE_UTF8
 
 # On Darwin, we need to run dsymutil so the debugging information ends
 # up in the right place.  On other platforms, it automatically gets