Thanks for your tips, Ian It works when I write in Makefile.am : CPPFLAGS =-DSRCDIR = "\"$(shell( cd $(srcdir) && pwd))/pics\"" with /pics under /src directory. I think I don't really understand why it works there and not CPPFLAGS =-DSRCDIR = "\"$(shell( cd $(srcdir) )/pics\"" with /pics in the project dir... But it works :))