+# Propagate 'HOME' through the environment.
+if 'HOME' in os.environ:
+ config.environment['HOME'] = os.environ['HOME']
+
+# Propagate 'INCLUDE' through the environment.
+if 'INCLUDE' in os.environ:
+ config.environment['INCLUDE'] = os.environ['INCLUDE']
+
+# Propagate 'LIB' through the environment.
+if 'LIB' in os.environ:
+ config.environment['LIB'] = os.environ['LIB']
+
+# Propagate LLVM_SRC_ROOT into the environment.
+config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')
+
+# Propagate PYTHON_EXECUTABLE into the environment
+config.environment['PYTHON_EXECUTABLE'] = getattr(config, 'python_executable',
+ '')