Fix python.el for Emacs 24, bump ELPA version to 0.26.1 (Bug#30633)
Since python.el is distributed via GNU ELPA, it should be functional
in earlier Emacs versions. Also fix some compile warnings.
* lisp/progmodes/python.el: Bump version to 0.26.1. Define
`prog-first-column' and `file-local-name' also at compile time, as
needed.
(inferior-python-mode-hook): Declare for the benefit of Emacs 24.3.
(python-nav-end-of-statement): Fix format string for assertion error.
(python-shell-tramp-refresh-process-environment): Don't `function'
quote a symbol which might not be fbound.
(python-mode): Only use prettify-symbols settings if they're bound.