doc: Explicitly list build dependencies for docs

Highlight the packages which need to be installed in order to build the
docs.

Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>

diff --git a/doc/build/documentation.rst b/doc/build/documentation.rst
index 011cd34..20b0fef 100644 (file)
--- a/doc/build/documentation.rst
+++ b/doc/build/documentation.rst
@@ -5,6 +5,17 @@ Building documentation
 
 The U-Boot documentation is based on the Sphinx documentation generator.
 
+In addition to the Python packages listed in ``doc/sphinx/requirements.txt``,
+the following dependencies are needed to build the documentation:
+
+* fontconfig
+
+* graphviz
+
+* imagemagick
+
+* texinfo (if building the `Infodoc documentation`_)
+
 HTML documentation
 ------------------