Fix fontifying of ::= in Makefiles

* lisp/progmodes/make-mode.el (makefile-match-dependency): Don't
fontify the POSIX immediate assignment operator ::= as a
dependency (bug#44319).

diff --git a/lisp/progmodes/make-mode.el b/lisp/progmodes/make-mode.el
index 01cc330dc2ea8de7c6a16422dcee6321a595be6a..ac3d08170979e2dd33700de43399f45767cfd401 100644 (file)
--- a/lisp/progmodes/make-mode.el
+++ b/lisp/progmodes/make-mode.el
@@ -1721,7 +1721,9 @@ matched in a rule action."
       (while (progn (skip-chars-forward makefile-dependency-skip bound)
                    (< (point) (or bound (point-max))))
        (forward-char)
-       (or (eq (char-after) ?=)
+        ;; The GNU immediate assignment operator is ":=", while the
+        ;; POSIX operator is "::=".
+       (or (looking-at ":?=")
            (get-text-property (1- (point)) 'face)
            (if (> (line-beginning-position) (+ (point-min) 2))
                (eq (char-before (line-end-position 0)) ?\\))