dev-libs/mongo-c-driver: fix building against >=sphinx-3

Closes: https://bugs.gentoo.org/716774
Package-Manager: Portage-2.3.99, Repoman-2.3.22
Signed-off-by: Thomas Deutschmann <whissi@gentoo.org>

dev-libs/mongo-c-driver/files/mongo-c-driver-1.16.2-sphinx.patch

@@ -0,0 +1,19 @@
+https://bugs.gentoo.org/716774
+
+--- a/build/sphinx/taglist.py
++++ b/build/sphinx/taglist.py
+@@ -24,7 +24,12 @@ THE SOFTWARE.
+ """
+ 
+ from docutils import nodes, utils
+-from sphinx.environment import NoUri
++
++try:
++    from sphinx.environment import NoUri
++except ImportError:
++    from sphinx.errors import NoUri
++
+ try:
+     from sphinx.util.compat import Directive
+ except ImportError:
+ 

dev-libs/mongo-c-driver/mongo-c-driver-1.16.2.ebuild

@@ -41,6 +41,7 @@ PATCHES=(
 	"${FILESDIR}/${PN}-1.14.0-no-docs.patch"
 	"${FILESDIR}/${PN}-1.16.2-enable-tests.patch" # enable tests with system libbson
 	"${FILESDIR}/${PN}-1.16.2-single-doc-job.patch"
+	"${FILESDIR}/${PN}-1.16.2-sphinx.patch"
 )
 
 src_prepare() {