1# http://www.gnu.org/software/make/manual/make.html#Syntax-of-Functions
2comma:= ,
3empty:=
4space:= $(empty) $(empty)
5foo:= a b c
6bar:= $(subst $(space),$(comma),$(foo))
7# bar is now `a,b,c'
8
9test:
10	echo $(bar)
11	echo $(subst ,repl,str)
12