Don't install libUnitTestMain.a. It might be useless without gtest headers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126632 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/unittest/UnitTestMain/Makefile b/utils/unittest/UnitTestMain/Makefile
index cec654f..3082779 100644
--- a/utils/unittest/UnitTestMain/Makefile
+++ b/utils/unittest/UnitTestMain/Makefile
@@ -27,4 +27,6 @@
   CPP.Flags += -DGTEST_HAS_PTHREAD=0
 endif
 
+NO_INSTALL = 1
+
 include $(LEVEL)/Makefile.common