https://raw.githubusercontent.com/Homebrew/formula-patches/master/autogen/allow-guile-2.2.diff

--- a/agen5/guile-iface.h
+++ b/agen5/guile-iface.h
@@ -9,7 +9,7 @@
 # error AutoGen does not work with this version of Guile
   choke me.
 
-#elif GUILE_VERSION < 201000
+#else
 # define AG_SCM_IS_PROC(_p)           scm_is_true( scm_procedure_p(_p))
 # define AG_SCM_LIST_P(_l)            scm_is_true( scm_list_p(_l))
 # define AG_SCM_PAIR_P(_p)            scm_is_true( scm_pair_p(_p))
@@ -24,9 +24,6 @@
 # define AG_SCM_TO_ULONG(_v)          ((unsigned long)scm_to_ulong(_v))
 # define AG_SCM_VEC_P(_v)             scm_is_vector(_v)
 
-#else
-# error unknown GUILE_VERSION
-  choke me.
 #endif
 
 #endif /* MUTATING_GUILE_IFACE_H_GUARD */
--- a/configure
+++ b/configure
@@ -14191,7 +14191,7 @@ $as_echo "no" >&6; }
 		PKG_CONFIG=""
 	fi
 fi
-  _guile_versions_to_search="2.0 1.8"
+  _guile_versions_to_search="2.2 2.0 1.8"
   if test -n "$GUILE_EFFECTIVE_VERSION"; then
     _guile_tmp=""
     for v in $_guile_versions_to_search; do