Roland Illig wrote:

 [ Makefile.inc weirdness ]

IMO, inclusion of all those Makefile.inc files is not necessary at all.
The last time I looked at this I could not find any useful content for
Makefile.inc apart from pkgsrc/Makefile.inc and pkgsrc/??/Makefile.inc.

Just set WEB_PREFIX and include the appropriate top-level Makefile.inc.
For de/errors/Makefile this would look like:

  WEB_PREFIX?=    ${.CURDIR}/../..
  .include "${WEB_PREFIX}/de/Makefile.inc"

> The top-level "Makefile.inc" should then include 
> "${WEB_PREFIX}/share/mk/web.site.mk".

> That way we can make sure that the toplevel "Makefile.inc" is included 
> in each subdirectory. Another simplification would be that the top-level 
> "Makefile.inc" has the following code:

Both should work with my proposal as well.

ciao
     Klaus