Re: Appending to builtin Automake variables from an included file

[Jan Engelhardt]

On Saturday 2009-02-28 11:16, Ralf Wildenhues wrote:
>> Modern Automake does support appending.  But only appending to a
>> variable that has already been set.
>
>Yes.  This is done primarily to be able to diagnose typos, e.g.,
>  foolish =
>  foo1ish += bar
>[...]
>Is it worth the hassle?  It's certainly a trade-off:
>- more work due to required initializations of all variables,
>- OTOH typos in variables can have rather subtle implications,
>  esp. if those variables are of the "magic automake" kind.

- "+=" could append to variables implicitly defined by make
  (the horror!). Though this does not happen with automake,
  users could walk into a trip when they have to write a manual
  Makefile (e.g. Makefile.in) without the use of Automake.