Index: unittests/CMakeLists.txt
===================================================================
--- unittests/CMakeLists.txt
+++ unittests/CMakeLists.txt
@@ -12,6 +12,14 @@
 
 include(${LLDB_PROJECT_ROOT}/cmake/LLDBDependencies.cmake)
 
+if (LLDB_BUILT_STANDALONE)
+  # Build the gtest library needed for unittests, if we have LLVM sources
+  # handy.
+  if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/unittest)
+    add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/unittest utils/unittest)
+  endif()
+endif()
+
 function(add_lldb_unittest test_name)
   add_unittest(LLDBUnitTests
     ${test_name}