Index: llvm/test/lit.cfg.py
===================================================================
--- llvm/test/lit.cfg.py
+++ llvm/test/lit.cfg.py
@@ -58,6 +58,9 @@
 # Set up OCAMLRUNPARAM to enable backtraces in OCaml tests.
 llvm_config.with_environment('OCAMLRUNPARAM', 'b')
 
+# Honor PYTHONPATH if set.
+llvm_config.with_system_environment('PYTHONPATH')
+
 # Provide the path to asan runtime lib 'libclang_rt.asan_osx_dynamic.dylib' if
 # available. This is darwin specific since it's currently only needed on darwin.