[gcc/devel/sphinx] contrib: use sphinx-build from a venv

[Martin Liska <marxin@gcc.gnu.org>]

https://gcc.gnu.org/g:3168c2f8ede30bdeb8adb607884101850ff50712

commit 3168c2f8ede30bdeb8adb607884101850ff50712
Author: Martin Liska <mliska@suse.cz>
Date:   Mon Jul 25 15:57:32 2022 +0200

    contrib: use sphinx-build from a venv
    
    maintainer-scripts/ChangeLog:
    
            * update_web_docs_git: Use sphinx-build from a venv so that
            we can use a recent version.

Diff:
---
 maintainer-scripts/update_web_docs_git | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/maintainer-scripts/update_web_docs_git b/maintainer-scripts/update_web_docs_git
index 996d29bfb68..6c38e213562 100755
--- a/maintainer-scripts/update_web_docs_git
+++ b/maintainer-scripts/update_web_docs_git
@@ -176,23 +176,14 @@ for file in $MANUALS; do
   fi
 done
 
-# The jit is a special-case, using sphinx rather than texinfo.
-# Specifically, the jit docs need sphinx 1.0 or later.
+# The jit is a special-case, using Sphinx rather than texinfo.
+# Specifically, the jit docs need Sphinx 3.0 or later.
 #
-# The jit/docs Makefile uses the executable $(SPHINXBUILD),
-# defaulting to "sphinx-build".
-#
-# sphinx is packaged in Fedora and EPEL 6 within "python-sphinx",
-# in RHEL 8 within "python3-sphinx",
-# and in openSUSE within "python-Sphinx".
-#
-# For EPEL6, python-sphinx is sphinx 0.6.6, which is missing various
-# directives (e.g. ":c:macro:"), so we need the variant
-# python-sphinx10 package.  The latter installs its executable as
-#   /usr/bin/sphinx-1.0-build
-# so we needed to override SPHINXBUILD with this when invoking "make".
+# Use the Sphinx installed in a virtual environment so that
+# we don't depend on a system package.
+
 pushd gcc/gcc/jit/docs
-make html || true
+make html SPHINXBUILD=/home/gccadmin/venv/bin/sphinx-build || true
 popd
 cp -a gcc/gcc/jit/docs/_build/html jit
 mkdir -p $DOCSDIR/jit