As most GNU Makefiles (or Makevars) tend to use '=' insead of ':=', I thought it might be helpful to point out that there is an important difference in the meaning. When a variable is defined like this: PKG_CPPFLAGS=whatever the RHS (whatever) is evaluated every time PKG_CPPFLAGS is used, and this can have undesirable side-effects, especially when whatever is a shell escape. On the other hand, with PKG_CPPFLAGS:=whatever the assignment only happens once, and this is normally what is expected to happen. Thus it is probably better to use := in most cases. Dominick [[alternative HTML version deleted]]