diff --git a/libcxx/utils/ci/runtimes/CMakeLists.txt b/libcxx/utils/ci/runtimes/CMakeLists.txt
index f46ef63b809c7..20980b530d4d3 100644
--- a/libcxx/utils/ci/runtimes/CMakeLists.txt
+++ b/libcxx/utils/ci/runtimes/CMakeLists.txt
@@ -13,14 +13,46 @@ if(POLICY CMP0077)
   cmake_policy(SET CMP0077 NEW)
 endif()
 
-set(PACKAGE_VERSION "11.0.0git")
-
 project(LLVM_RUNTIMES)
 
-# Include individual projects
-set(LLVM_ENABLE_PROJECTS "" CACHE STRING "Semicolon-separated list of runtimes to build.")
+find_package(Python3 COMPONENTS Interpreter)
+if(NOT Python3_Interpreter_FOUND)
+  message(WARNING "Python3 not found, using python2 as a fallback")
+  find_package(Python2 COMPONENTS Interpreter REQUIRED)
+  if(Python2_VERSION VERSION_LESS 2.7)
+    message(SEND_ERROR "Python 2.7 or newer is required")
+  endif()
+
+  # Treat python2 as python3
+  add_executable(Python3::Interpreter IMPORTED)
+  set_target_properties(Python3::Interpreter PROPERTIES
+    IMPORTED_LOCATION ${Python2_EXECUTABLE})
+  set(Python3_EXECUTABLE ${Python2_EXECUTABLE})
+endif()
+
+# This needs to be set before we add any Lit target for `add_lit_target` to
+# select the right Lit to run the tests.
+set(LLVM_LIT_OUTPUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/bin")
 
+# Automatically define a few variables that are normally set globally by LLVM.
+# This is to keep some amount of similarity between the global LLVM build and
+# this minimal build.
 set(LLVM_UMBRELLA_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../../../..")
+list(APPEND CMAKE_MODULE_PATH "${LLVM_UMBRELLA_ROOT}/libcxx/cmake/Modules")
+include(HandleOutOfTreeLLVM)
+
+# Override the external Lit to make sure we use the one we generate below.
+# TODO: We can remove this once we start relying on the in-tree version of Lit
+#       in HandleOutOfTreeLLVM.
+set(LLVM_DEFAULT_EXTERNAL_LIT "")
+
+# Include individual runtime projects
+set(LLVM_ENABLE_PROJECTS "" CACHE STRING "Semicolon-separated list of runtimes to build.")
 foreach(project IN LISTS LLVM_ENABLE_PROJECTS)
-    add_subdirectory("${LLVM_UMBRELLA_ROOT}/${project}" "${CMAKE_CURRENT_BINARY_DIR}/${project}")
+  add_subdirectory("${LLVM_UMBRELLA_ROOT}/${project}" "${CMAKE_CURRENT_BINARY_DIR}/${project}")
 endforeach()
+
+# Generate the llvm-lit wrapper, needed for testing. This must be done after
+# the projects have been added, since the wraper is only generated correctly
+# if the test suites have already been added with add_lit_target.
+add_subdirectory("${LLVM_UMBRELLA_ROOT}/llvm/utils/llvm-lit" "${CMAKE_CURRENT_BINARY_DIR}/llvm-lit")