I got as far as this collection of patches: https://paste.ubuntu.com/p/wvRzpByDXT/ :
--- a/docsrc/exts/sphinxlocal/writers/manpage.py
+++ b/docsrc/exts/sphinxlocal/writers/manpage.py
@@ -14,7 +14,6 @@
 
 from docutils import nodes
 from sphinx.writers.manpage import (
-    MACRO_DEF,
     ManualPageWriter,
     ManualPageTranslator as BaseTranslator
 )
@@ -73,9 +72,6 @@
         self._docinfo['version'] = builder.config.version
         self._docinfo['manual_group'] = builder.config.project
 
-        # since self.append_header() is never called, need to do this here
-        self.body.append(MACRO_DEF)
-
         # overwritten -- don't wrap literal_block with font calls
         self.defs['literal_block'] = ('.sp\n.nf\n', '\n.fi\n')
 
--- a/docsrc/exts/sphinxlocal/writers/manpage.py
+++ b/docsrc/exts/sphinxlocal/writers/manpage.py
@@ -13,6 +13,8 @@
 """
 
 from docutils import nodes
+from time import strftime
+
 from sphinx.writers.manpage import (
     ManualPageWriter,
     ManualPageTranslator as BaseTranslator
@@ -21,7 +23,6 @@
 
 from sphinx import addnodes
 from sphinx.locale import admonitionlabels, _
-from sphinx.util.osutil import ustrftime
 
 class CyrusManualPageWriter(ManualPageWriter):
 
@@ -66,7 +67,7 @@
         if builder.config.today:
             self._docinfo['date'] = builder.config.today
         else:
-            self._docinfo['date'] = ustrftime(builder.config.today_fmt
+            self._docinfo['date'] = strftime(builder.config.today_fmt
                                               or _('%B %d, %Y'))
         self._docinfo['copyright'] = builder.config.copyright
         self._docinfo['version'] = builder.config.version
diff --git a/docsrc/exts/sphinxlocal/roles/saslman.py b/docsrc/exts/sphinxlocal/roles/saslman.py
index f881d98f..bcafeece 100644
--- a/docsrc/exts/sphinxlocal/roles/saslman.py
+++ b/docsrc/exts/sphinxlocal/roles/saslman.py
@@ -18,7 +18,6 @@ from string import Template
 import re
 
 def setup(app):
-    app.info('Initializing saslman plugin')
     app.add_crossref_type('saslman', 'saslman', '%s', nodes.generated)
     return
 
diff --git a/docsrc/exts/sphinxlocal/builders/manpage.py b/docsrc/exts/sphinxlocal/builders/manpage.py
index a6281f79..126839e0 100644
--- a/docsrc/exts/sphinxlocal/builders/manpage.py
+++ b/docsrc/exts/sphinxlocal/builders/manpage.py
@@ -21,7 +21,6 @@ from docutils.frontend import OptionParser
 from sphinx import addnodes
 from sphinx.errors import SphinxError
 from sphinx.builders import Builder
-from sphinx.environment import NoUri
 from sphinx.util.nodes import inline_all_toctrees
 from sphinx.util.console import bold, darkgreen
 from sphinx.writers.manpage import ManualPageWriter


That moves along a bit, but then fails with;
sed -e 's,[@]LIB_DOOR[@],,g' -e 's,[@]SASL_DL_LIB[@],-ldl,g' -e 's,[@]LIBS[@],-lresolv ,g' -e 's,[@]VERSION[@],2.1.27,g' -e 's,[@]libdir[@],/usr/lib/x86_64-linux-gnu,g' -e 's,[@]prefix[@],/usr,g' -e 's,[@]exec_prefix[@],/usr,g' -e 's,[@]includedir[@],/usr/include,g' < ../libsasl2.pc.in > libsasl2.pc
/usr/bin/sphinx-build -d docsrc/.doctrees -n -q -b cyrman ./docsrc ./man
WARNING: The config value `author' has type `list', defaults to `str'.
WARNING: The config value `epub_author' has type `str', defaults to `list'.
WARNING: The config value `epub_publisher' has type `str', defaults to `list'.

Extension error:
Handler <function check_confval_types at 0x7f20c3a1c4c0> for event 'config-inited' threw an exception (exception: 'list' object has no attribute 'translate')
['The Cyrus Team']
make[4]: *** [Makefile:1166: man/.sphinx-build.stamp] Error 2
make[4]: Leaving directory '/home/ubuntu/git/packages/cyrus-sasl2/cyrus-sasl2/build-heimdal'
make[3]: *** [Makefile:686: all-recursive] Error 1
make[3]: Leaving directory '/home/ubuntu/git/packages/cyrus-sasl2/cyrus-sasl2/build-heimdal'
make[2]: *** [Makefile:556: all] Error 2
make[2]: Leaving directory '/home/ubuntu/git/packages/cyrus-sasl2/cyrus-sasl2/build-heimdal'
dh_auto_build: error: cd build-heimdal && make -j4 sasldir=/usr/lib/x86_64-linux-gnu/sasl2 returned exit code 2
make[1]: *** [debian/rules:164: override_dh_auto_build] Error 25
make[1]: Leaving directory '/home/ubuntu/git/packages/cyrus-sasl2/cyrus-sasl2'
make: *** [debian/rules:122: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2