Highlight external links in HTML documentation

Based on MediaWiki's monobook skin.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

Makefile.am

@@ -82,6 +82,7 @@ DIRS = \
 	devel \
 	doc \
 	doc/examples \
+	doc/examples/css \
 	doc/examples/gnt-debug \
 	doc/examples/hooks \
 	test/data/htools \
@@ -584,6 +585,7 @@ $(RUN_IN_TEMPDIR): | stamp-directories
 doc/html/index.html: $(docrst) doc/conf.py configure.ac \
 	$(RUN_IN_TEMPDIR) lib/build/sphinx_ext.py \
 	lib/build/shell_example_lexer.py lib/opcodes.py lib/ht.py \
+	doc/css/style.css \
 	| $(BUILT_PYTHON_SOURCES)
 	@test -n "$(SPHINX)" || \
 	    { echo 'sphinx-build' not found during configure; exit 1; }
@@ -812,6 +814,7 @@ EXTRA_DIST = \
 	tools/vcluster-setup.in \
 	$(docrst) \
 	doc/conf.py \
+	doc/css/style.css \
 	doc/html \
 	$(BUILT_EXAMPLES:%=%.in) \
 	doc/examples/ganeti.default \

doc/conf.py

@@ -134,7 +134,9 @@ html_theme = "default"
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = []
+html_static_path = ["css"]
+
+html_style = "style.css"
 
 # If not "", a "Last updated on:" timestamp is inserted at every page bottom,
 # using the given strftime format.

doc/css/style.css

+@import url(default.css);
+
+a.external {
+  /* Based on MediaWiki's monobook skin (licenced as GPL) */
+  background: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs%2B9AAAAVklEQVR4Xn3PgQkAMQhDUXfqTu7kTtkpd5RA8AInfArtQ2iRXFWT2QedAfttj2FsPIOE1eCOlEuoWWjgzYaB%2FIkeGOrxXhqB%2BuA9Bfcm0lAZuh%2BYIeAD%2BcAqSz4kCMUAAAAASUVORK5CYII%3D") no-repeat scroll right center transparent;
+  padding-right: 13px;
+}