Variable: makefile-macro-assign
makefile-macro-assign is a customizable variable defined in
make-mode.el.gz.
Value
" = "
Documentation
String to append to all macro names inserted by makefile-insert-macro.
The normal value should be " = ", since this is what standard make expects. However, newer makes such as dmake allow a larger variety of different macro assignments, so you might prefer to use " += " or " := " .
Source Code
;; Defined in /usr/src/emacs/lisp/progmodes/make-mode.el.gz
(defcustom makefile-macro-assign " = "
"String to append to all macro names inserted by `makefile-insert-macro'.
The normal value should be \" = \", since this is what
standard make expects. However, newer makes such as dmake
allow a larger variety of different macro assignments, so you
might prefer to use \" += \" or \" := \" ."
:type 'string)