I use Flycheck to check C files, and have a fairly elaborate variable setup for GCC to allow it to work correctly. However, due to having Clang on my system (for reasons unrelated to code), Flycheck always assumes that this is what I want to use, forcing me to manually switch checkers all the time.
I've tried to look for a way to permanently disable Clang as a checker, but I've come up empty. Help would be appreciated.
You should be able to add c/c++-clang to the variable flycheck-disabled-checkers. From the documentation of this variable (C-h v flycheck-disabled-checkers):
A list of Flycheck syntax checkers to exclude from automatic selection. Flycheck will never automatically select a syntax checker in this list, regardless of the value of `flycheck-checkers'.
Simply add (add-to-list 'flycheck-disabled-checkers 'c/c++-clang) to your init file.