The latter is not officially "wrong", but *is* terribly anachronistic.
I think automake documentation or comments call that syntax obsolescent.
* cfg.mk (_makefile_at_at_check_exceptions): Exempt @SCHEMADIR@
and @SYSCONFDIR@ uses -- there are no Makefile variables for those.
* docs/Makefile.am: Use $(INSTALL), not @INSTALL@.
* examples/dominfo/Makefile.am: Similar.
* examples/domsuspend/Makefile.am: Similar.
* proxy/Makefile.am: Similar.
* python/Makefile.am: Similar.
* python/tests/Makefile.am: Similar.
* src/Makefile.am: Similar.
* tests/Makefile.am: Similar.
* Makefile.am: Add examples/dominfo examples/domsuspend examples/python
as SUBDIRS
* configure.in: Update AC_OUTPUT for new/old Makefiles
* docs/Makefile.am: Remove examples from SUBDIRS
* docs/examples/info1.c: Move to examples/dominfo/info1.c
* docs/examples/suspend.c: Move to examples/domsuspend/suspend.c
* docs/examples: Remove all remaining files
* docs/examples/python: Moved to examples/python/
* examples/dominfo/Makefile.am, examples/domsuspend/Makefile.am: New
build files
* libvirt.spec.in: Update to take account of moved examples
