_loader/loader: cythonize valid_chars_name

- Create a new _loader/utils.pyx cython module for functions cythonized
in the loader module.

- Move valid_chars_name from loader to utils and cythonize.

This function is called extensively, and easy to extract

1 files changed, 4 insertions, 1 deletions

diff --git a/.pylintrc b/.pylintrc
index e0941862f..c33aa48b8 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -3,7 +3,10 @@
 # A comma-separated list of package or module names from where C extensions may
 # be loaded. Extensions are loading into the active Python interpreter and may
 # run arbitrary code
-extension-pkg-whitelist=buildstream._variables,buildstream._yaml
+extension-pkg-whitelist=
+    buildstream._loader._loader,
+    buildstream._variables,
+    buildstream._yaml
 
 # Add files or directories to the blacklist. They should be base names, not
 # paths.