diff --git a/CTestCustom.cmake.in b/CTestCustom.cmake.in
index 0e61da441..1a466889b 100644
--- a/CTestCustom.cmake.in
+++ b/CTestCustom.cmake.in
@@ -44,6 +44,10 @@ 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"
+
+  # Ignore clang's summary warning, assuming prior text has matched some
+  # other warning expression:
+  "[0-9,]+ warnings? generated."
   )
 
 IF(NOT "@CMAKE_GENERATOR@" MATCHES "Xcode")