Use ?= to set variables which may be imported from upper-level

Makefiles.

diff --git a/lisp/Makefile.lisp b/lisp/Makefile.lisp
index 2e8ab50..fce2a66 100644 (file)
--- a/lisp/Makefile.lisp
+++ b/lisp/Makefile.lisp
@@ -1,27 +1,18 @@
 PACKAGE        = liece
 VERSION        = 1.4.7
 
-ifndef EMACS
-       EMACS   = emacs
-endif
-ifndef XEMACS
-       XEMACS  = xemacs
-endif
-FLAGS  = -batch -q -no-site-file
-TAR    = tar
-
-ifndef PREFIX
-       PREFIX  = NONE
-endif
-ifndef LISPDIR
-       LISPDIR = NONE
-endif
-PACKAGEDIR = NONE
-VERSION_SPECIFIC_LISPDIR = NONE
-
-GOMI     = liece-setup.el *.elc
-
-all: elc
+EMACS ?= emacs
+XEMACS ?= xemacs
+FLAGS ?= -batch -q -no-site-file
+TAR ?= tar
+PREFIX ?= NONE
+LISPDIR        ?= NONE
+PACKAGEDIR ?= NONE
+VERSION_SPECIFIC_LISPDIR ?= NONE
+
+GOMI = liece-setup.el *.elc
+
+all:: elc
 
 elc: 
        $(EMACS) $(FLAGS) -l ./liece-make.el -f autoload-liece \
@@ -43,5 +34,5 @@ install-package: package
        $(XEMACS) $(FLAGS) -l ./liece-make.el -f install-liece-package \
                $(PACKAGEDIR)
 
-clean:
+clean::
        -rm -f $(GOMI)