diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa14353b8..89f4e5221 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -286,3 +286,10 @@ add_custom_target("check"
 if (BUILD_TV)
   add_dependencies("check" "alive-tv" "quick-fuzz" "tv")
 endif()
+
+# EXTERNAL_PROJECTS option that works analogous to LLVM's LLVM_EXTERNAL_PROJECTS option
+foreach(EXTERNAL_PROJECT IN LISTS EXTERNAL_PROJECTS)
+  canonicalize_tool_name(${EXTERNAL_PROJECT} PROJECT_CANON)
+  message(STATUS "Adding external project ${EXTERNAL_PROJECT} at ${EXTERNAL_${PROJECT_CANON}_SOURCE_DIR}")
+  add_subdirectory(${EXTERNAL_${PROJECT_CANON}_SOURCE_DIR} ${EXTERNAL_PROJECT})
+endforeach()