Variable: compilation-gcpro
compilation-gcpro is a buffer-local variable defined in compile.el.gz.
Documentation
Internal variable used to keep some values from being GC'd.
Source Code
;; Defined in /usr/src/emacs/lisp/progmodes/compile.el.gz
(defvar-local compilation-gcpro nil
"Internal variable used to keep some values from being GC'd.")