diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
index e43ea74e00f..2974726a7f7 100644
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@@ -58,6 +58,9 @@ if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
   set(LLVM_LIBRARY_OUTPUT_INTDIR ${LLVM_LIBRARY_DIR})
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${LLVM_TOOLS_BINARY_DIR})
 
+  # This variable makes sure that e.g. llvm-lit is found.
+  set(LLVM_MAIN_SRC_DIR ${LLVM_BUILD_MAIN_SRC_DIR})
+
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)