Added a error when attempt to create a distribution on a sub directory

Makefile.in

@@ -25,10 +25,10 @@ install: installdirs
 	$(POST_INSTALL)     # Post-install commands follow.
 
 dist: FORCE
-	$(fn_remove_dist_archive)
+	$(fn_pre_dist)
 	dir='$(srcdir)' && $(fn_append_files_to_dist_archive) \
 	    $(notdir $(INSTALL_DOCS))
-	$(fn_finalize_dist_archive)
+	$(fn_post_dist)
 
 installdirs:
 	$(INSTALL) -d '$(DESTDIR)$(docdir)'

bootstrap.mk.in

@@ -201,11 +201,21 @@ maintainer-clean-generic:
 	@echo 'deletes files that may need special tools to rebuild.'
 
 
-fn_remove_dist_archive = rm -f '$(DIST_ARCHIVE)'
+fn_top_pre_dist = \
+	test x"$(builddir)" = x"$(top_builddir)" || { \
+	    echo "ERROR: cannot create a distribution on a sub directory"; \
+	    echo '       $$ cd $(top_builddir) && make dist'; \
+	    exit 1; \
+	} >&2
+
+fn_pre_dist = \
+	@$(fn_top_pre_dist); \
+	echo 'rm -f $(DIST_ARCHIVE)'; \
+	rm -f '$(DIST_ARCHIVE)'
 
 fn_append_files_to_dist_archive = tar -C $$dir -rf '$(DIST_ARCHIVE)' --transform s,'^','$(distdir)/',
 
-fn_finalize_dist_archive = \
+fn_post_dist = \
 	@echo 'dir="$(srcdir)" && $(fn_append_files_to_dist_archive)'; \
 	echo '    Makefile.in'; \
 	dir='$(srcdir)' && $(fn_append_files_to_dist_archive) \
@@ -258,6 +268,7 @@ fn_titlelize = { sed -e 1h -e 1s/./=/g -e 1p -e 1x -e '$$p' -e '$$x'; }
 	        distdir="$(distdir)/$$subdir" \
 	        fn_finalize_top_dist_archive=':' \
 	        TOP_DISTCLEAN_FILES='' \
+	        fn_top_pre_dist=':' \
 	    ; \
 	done;
 

doc/Makefile.in

@@ -23,10 +23,10 @@ install: all installdirs
 	$(POST_INSTALL)     # Post-install commands follow.
 
 dist: FORCE
-	$(fn_remove_dist_archive)
+	$(fn_pre_dist)
 	dir='$(srcdir)' && $(fn_append_files_to_dist_archive) \
 	    man.1
-	$(fn_finalize_dist_archive)
+	$(fn_post_dist)
 
 $(builddir)/$(PACKAGE)$(man1ext).gz: $(srcdir)/man.1
 	gzip -c $^ > $@

src/Makefile.in

@@ -55,7 +55,7 @@ installcheck: install
 	cd '$(DESTDIR)$(pkglibdir)' && $(PYTHON) $(PYTHONFLAGS) $(TEST_SCRIPT) $(ARGUMENTS)
 
 dist: $(srcdir)/setup.py FORCE
-	$(fn_remove_dist_archive)
+	$(fn_pre_dist)
 	rm -rf $(srcdir)/build
 	$(PYTHON) $(PYTHONFLAGS) $(srcdir)/setup.py build
 	dir='$(srcdir)/build/lib' && $(fn_append_files_to_dist_archive) \
@@ -65,7 +65,7 @@ dist: $(srcdir)/setup.py FORCE
 	    main.in \
 	    postinstall.sh.in \
 	    setup.py.in
-	$(fn_finalize_dist_archive)
+	$(fn_post_dist)
 
 $(builddir)/$(PACKAGE): $(srcdir)/main.in
 	cat $^ \

tools/Makefile.in

@@ -23,10 +23,10 @@ install: all installdirs
 	$(POST_INSTALL)     # Post-install commands follow.
 
 dist: FORCE
-	$(fn_remove_dist_archive)
+	$(fn_pre_dist)
 	dir='$(srcdir)' && $(fn_append_files_to_dist_archive) \
 	    completion.bash
-	$(fn_finalize_dist_archive)
+	$(fn_post_dist)
 
 $(builddir)/$(PACKAGE): $(srcdir)/completion.bash
 	cp $^ $@