diff --git a/core/clang/config.mk b/core/clang/config.mk
index bdd18d8..9ae2693 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -42,6 +42,11 @@
 CLANG_CONFIG_EXTRA_CFLAGS += \
   -Werror=int-conversion
 
+# Workaround for ccache with clang.
+# See http://petereisentraut.blogspot.com/2011/05/ccache-and-clang.html.
+CLANG_CONFIG_EXTRA_CFLAGS += \
+  -Wno-unused-command-line-argument
+
 CLANG_CONFIG_UNKNOWN_CFLAGS := \
   -finline-limit=64 \
   -fno-canonical-system-headers \