build: change to gnulib module list should rerun bootstrap

* autogen.sh (curr_status): Also include hash of bootstrap.conf
when checking for changes that require bootstrap rerun.
* cfg.mk (_update_required): Likewise.

autogen.sh

@@ -65,7 +65,8 @@ fi
 # Ensure that whenever we pull in a gnulib update or otherwise change to a
 # different version (i.e., when switching branches), we also rerun ./bootstrap.
 curr_status=.git-module-status
-t=$(git submodule status|sed 's/^[ +-]//;s/ .*//')
+t=$(git submodule status|sed 's/^[ +-]//;s/ .*//'; \
+    git hash-object bootstrap.conf)
 if test "$t" = "$(cat $curr_status 2>/dev/null)"; then
     : # good, it's up to date, all we need is autoreconf
     autoreconf -if

cfg.mk

@@ -279,7 +279,8 @@ ifeq (0,$(MAKELEVEL))
   # b653eda3ac4864de205419d9f41eec267cb89eeb
   _submodule_hash = sed 's/^[ +-]//;s/ .*//'
   _update_required := $(shell						\
-      actual=$$(git submodule status | $(_submodule_hash));		\
+      actual=$$(git submodule status | $(_submodule_hash);		\
+		git hash-object bootstrap.conf);			\
       stamp="$$($(_submodule_hash) $(_curr_status) 2>/dev/null)";	\
       test "$$stamp" = "$$actual"; echo $$?)
   ifeq (1,$(_update_required))