[mod] Makefile: make CONTACT_URL optional

Makefile

@@ -6,7 +6,7 @@ export GIT_URL=https://github.com/searx/searx
 export GIT_BRANCH=master
 export SEARX_URL=https://searx.me
 export DOCS_URL=https://searx.github.io/searx
-export CONTACT_URL=mailto:contact@example.com
+# export CONTACT_URL=mailto:contact@example.com
 # END Makefile setup
 
 include utils/makefile.include

searx/templates/oscar/base.html

@@ -88,8 +88,8 @@
                     {{ _('Powered by') }} <a href="{{ brand.DOCS_URL }}">searx</a> - {{ searx_version }} - {{ _('a privacy-respecting, hackable metasearch engine') }}<br/>
                     <a href="{{ brand.GIT_URL }}">{{ _('Source code') }}</a> |
                     <a href="{{ brand.ISSUE_URL }}">{{ _('Issue tracker') }}</a> |
-                    <a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a> |
-                    <a href="{{ brand.CONTACT_URL }}">{{ _('Contact instance maintainer') }}</a>
+                    <a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a>{% if brand.CONTACT_URL %} |
+                    <a href="{{ brand.CONTACT_URL }}">{{ _('Contact instance maintainer') }}</a>{% endif %}
                 </small>
             </p>
         </div>

searx/templates/simple/base.html

@@ -54,8 +54,8 @@
     {{ _('Powered by') }} <a href="{{ url_for('about') }}">searx</a> - {{ searx_version }} — {{ _('a privacy-respecting, hackable metasearch engine') }}<br/>
         <a href="{{ brand.GIT_URL }}">{{ _('Source code') }}</a> |
         <a href="{{ brand.ISSUE_URL }}">{{ _('Issue tracker') }}</a> |
-        <a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a> |
-        <a href="{{ brand.CONTACT_URL }}">{{ _('Contact instance maintainer') }}</a>
+        <a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a>{% if brand.CONTACT_URL %} |
+        <a href="{{ brand.CONTACT_URL }}">{{ _('Contact instance maintainer') }}</a>{% endif %}
     </p>
   </footer>
   <!--[if gte IE 9]>-->