+# Allow cfg.mk to override these.
+_build-aux ?= build-aux
+_autoreconf ?= autoreconf
+
+# Ensure that $(VERSION) is up to date for dist-related targets, but not
+# for others: rerunning autoreconf and recompiling everything isn't cheap.
+_have-git-version-gen := \
+ $(shell test -f $(srcdir)/$(_build-aux)/git-version-gen && echo yes)
+ifeq ($(_have-git-version-gen)0,yes$(MAKELEVEL))
+ _is-dist-target ?= $(filter-out %clean, \
+ $(filter maintainer-% dist% alpha beta major,$(MAKECMDGOALS)))
+ _is-install-target ?= $(filter-out %check, $(filter install%,$(MAKECMDGOALS)))
+ ifneq (,$(_is-dist-target)$(_is-install-target))
+ _curr-ver := $(shell cd $(srcdir) \
+ && $(_build-aux)/git-version-gen .tarball-version)
+ ifneq ($(_curr-ver),$(VERSION))
+ ifeq ($(_curr-ver),UNKNOWN)
+ $(info WARNING: unable to verify if $(VERSION) is the correct version)
+ else
+ ifneq (,$(_is-install-target))
+ # GNU Coding Standards state that 'make install' should not cause
+ # recompilation after 'make all'. But as long as changing the version
+ # string alters config.h, the cost of having 'make all' always have an
+ # up-to-date version is prohibitive. So, as a compromise, we merely
+ # warn when installing a version string that is out of date; the user
+ # should run 'autoreconf' (or something like 'make distcheck') to
+ # fix the version, 'make all' to propagate it, then 'make install'.
+ $(info WARNING: version string $(VERSION) is out of date;)
+ $(info run '$(MAKE) _version' to fix it)
+ else
+ $(info INFO: running autoreconf for new version string: $(_curr-ver))
+ _dummy := $(shell $(MAKE) $(AM_MAKEFLAGS) _version)
+ endif
+ endif
+ endif
+ endif
+endif
+
+.PHONY: _version
+_version:
+ cd $(srcdir) && rm -rf autom4te.cache .version && $(_autoreconf)
+