diff --git a/unittests/Makefile.unittest b/unittests/Makefile.unittest
index 3bed567503d..6001c436e5a 100644
--- a/unittests/Makefile.unittest
+++ b/unittests/Makefile.unittest
@@ -23,6 +23,9 @@ LLVMUnitTestExe = $(BuildMode)/$(TESTNAME)Tests$(EXEEXT)
 CPP.Flags += -I$(LLVM_SRC_ROOT)/utils/unittest/googletest/include
 CPP.Flags += $(NO_MISSING_FIELD_INITIALIZERS) $(NO_VARIADIC_MACROS)
 CPP.Flags += -DGTEST_HAS_RTTI=0
+# libstdc++'s TR1 <tuple> header depends on RTTI and uses C++'0x features not
+# supported by Clang, so force googletest to use its own tuple implementation.
+CPP.Flags += -DGTEST_USE_OWN_TR1_TUPLE
 
 TESTLIBS = -lGoogleTest -lUnitTestMain
 
diff --git a/utils/unittest/UnitTestMain/Makefile b/utils/unittest/UnitTestMain/Makefile
index 16ac38b5688..202ccb8eeed 100644
--- a/utils/unittest/UnitTestMain/Makefile
+++ b/utils/unittest/UnitTestMain/Makefile
@@ -18,5 +18,8 @@ REQUIRES_RTTI = 1
 CPP.Flags += -I$(LLVM_SRC_ROOT)/utils/unittest/googletest/include
 CPP.Flags += $(NO_MISSING_FIELD_INITIALIZERS) $(NO_VARIADIC_MACROS)
 CPP.Flags += -DGTEST_HAS_RTTI=0
+# libstdc++'s TR1 <tuple> header depends on RTTI and uses C++'0x features not
+# supported by Clang, so force googletest to use its own tuple implementation.
+CPP.Flags += -DGTEST_USE_OWN_TR1_TUPLE
 
 include $(LEVEL)/Makefile.common
diff --git a/utils/unittest/googletest/Makefile b/utils/unittest/googletest/Makefile
index b6e3e68a330..bfd35a4f510 100644
--- a/utils/unittest/googletest/Makefile
+++ b/utils/unittest/googletest/Makefile
@@ -21,6 +21,9 @@ REQUIRES_RTTI = 1
 CPP.Flags += -I$(LLVM_SRC_ROOT)/utils/unittest/googletest/include
 CPP.Flags += $(NO_MISSING_FIELD_INITIALIZERS) $(NO_VARIADIC_MACROS)
 CPP.Flags += -DGTEST_HAS_RTTI=0
+# libstdc++'s TR1 <tuple> header depends on RTTI and uses C++'0x features not
+# supported by Clang, so force googletest to use its own tuple implementation.
+CPP.Flags += -DGTEST_USE_OWN_TR1_TUPLE
 
 ifeq ($(HOST_OS),MingW)
   CPP.Flags += -DGTEST_OS_WINDOWS=1