build: Work around gnu-efi build system issue
diff --git a/stage23/Makefile b/stage23/Makefile
index 8ceb753e..17cb128e 100644
--- a/stage23/Makefile
+++ b/stage23/Makefile
@@ -229,6 +229,9 @@ endif
$(BUILDDIR)/gnu-efi:
cp -r ../gnu-efi $(BUILDDIR)/
+ # gnu-efi's build system is broken and fails to actually detect clang.
+ # This is a workaround.
+ sed -i 's/-maccumulate-outgoing-args//g' $(BUILDDIR)/gnu-efi/Make.defaults
ifeq ($(TARGET), uefi)
