* build-aux/git-hooks/pre-commit: Use EMACS_GIT_CORE_WHITESPACE, not the global core.whitespace, for whitespace checks when committing. This defaults to empty, which means to use the Git default, and this should fix Bug#80428 “C indentation in .gitattributes, macros in .dir-locals.el”. The environment variable is a better way to temporarily override the default.