build/unittests: Fix llvm-config names for gtest libraries, and bring Makefile
library names in line with those used by CMake.
 - Patch by Johannes Obermayr, with tweaks by me.

llvm-svn: 146706
diff --git a/llvm/unittests/Makefile.unittest b/llvm/unittests/Makefile.unittest
index 580ad7d..bd32aed 100644
--- a/llvm/unittests/Makefile.unittest
+++ b/llvm/unittests/Makefile.unittest
@@ -34,7 +34,7 @@
   CPP.Flags += -DGTEST_HAS_PTHREAD=0
 endif
 
-TESTLIBS = -lGoogleTest -lUnitTestMain
+TESTLIBS = -lgtest -lgtest_main
 
 ifeq ($(ENABLE_SHARED), 1)
   ifneq (,$(RPATH))