Bug report

Bug description:

I think there is some leftover code in sysconfig.expand_makefile_vars (4a53a39):

The _findvar1_rx and _findvar2_rx variables are not declared at all (they were moved to sysconfig/__main__.py). Since the function is publicly named (but not exported nor documented), I prefer backporting the changes of #110785, namely re-use the patterns as is.

cc @FFY00

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-128978: Fix a NameError in sysconfig.expand_makefile_vars #128979
• [3.13] gh-128978: Fix a NameError in sysconfig.expand_makefile_vars (GH-128979) #129065
• [3.12] gh-128978: Fix a NameError in sysconfig.expand_makefile_vars (GH-128979) #129066 (not needed)