Prevent Plantuml from trying to use X.

Reviewers: #reviewers, douardda

Reviewed By: #reviewers, douardda

Differential Revision: https://forge.softwareheritage.org/D743

docs/images/Makefile

@@ -27,7 +27,7 @@ py-deps-ext.dot: $(PY_DEPGRAPH) $(PY_REQUIREMENTS)
 	dot -T svg $< > $@
 
 %.svg: %.uml
-	plantuml -tsvg $<
+	DISPLAY="" plantuml -tsvg $<
 
 clean:
 	-rm -f $(DEP_GRAPHS) $(UML_DIAGS)

[Phabricator Migration user]

Some references in the commit message have been migrated:

• D743 is now !14 (closed)