As it is documented like this:
If SUBDIRS is defined conditionally using Automake conditionals,
Automake will define DIST_SUBDIRS automatically from the possible
values of SUBDIRS in all conditions.
So we don't need to re-define DIST_SUBDIRS in Makefile.am unless
we use AC_SUBST to define SUBDIRS.
Patch from Quentin Glidic
fc-validate conf.d test
if ENABLE_DOCS
SUBDIRS += doc
-DIST_SUBDIRS = $(SUBDIRS)
-else
-DIST_SUBDIRS = $(SUBDIRS) doc
endif
AUTOMAKE_OPTIONS = dist-bzip2