There are a few typos in configure.ac and pyconfig.h.in:

• Line 6415 of configure.ac: useable → usable (appears twice on same line)
• Line 6505 of configure.ac: defauly → default
• Line 1602 of pyconfig.h.in: useable → usable (appears twice on same line)

These are all in comments and doc strings, not in code logic.

Linked PRs

• gh-145961: Fix typos in configure.ac and pyconfig.h.in #145962