diff --git a/CTestCustom.cmake.in b/CTestCustom.cmake.in
index 286b3c9a9..9eee65588 100644
--- a/CTestCustom.cmake.in
+++ b/CTestCustom.cmake.in
@@ -48,6 +48,7 @@ SET(CTEST_CUSTOM_WARNING_EXCEPTION
   "cc-3968 CC: WARNING File.*" # "implicit" truncation by static_cast
   "ld: warning: directory not found for option .-(F|L)"
   "warning.*This version of Mac OS X is unsupported"
+  "clang.*: warning: argument unused during compilation: .-g"
 
   # Ignore clang's summary warning, assuming prior text has matched some
   # other warning expression: