[gtk-osx] Update gtk-doc, make python3 a soft dependency.

[John Ralls <jralls src gnome org>]

commit e7c31775e1052d40a1f4e0ee703af28c75410cbb
Author: John Ralls <jralls ceridwen us>
Date:   Wed Jul 31 19:28:29 2019 -0700

    Update gtk-doc, make python3 a soft dependency.

 modulesets-stable/gtk-osx-bootstrap.modules | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/modulesets-stable/gtk-osx-bootstrap.modules b/modulesets-stable/gtk-osx-bootstrap.modules
index b9be568..f3f434b 100644
--- a/modulesets-stable/gtk-osx-bootstrap.modules
+++ b/modulesets-stable/gtk-osx-bootstrap.modules
@@ -116,14 +116,17 @@
     </dependencies>
   </autotools>
 
-  <autotools id="gtk-doc">
-    <branch version="1.29" module="gtk-doc/1.29/gtk-doc-1.29.tar.xz"
-            hash="sha256:14578e002496567276d310a62c9ffd6c56ee8806ce5079ffb0b81c4111f586b1"/>
+  <autotools id="gtk-doc" autogen-sh="configure">
+    <branch version="1.30" module="gtk-doc/1.30/gtk-doc-1.30.tar.xz"
+            hash="sha256:a4f6448eb838ccd30d76a33b1fd095f81aea361f03b12c7b23df181d21b7069e"/>
     <dependencies>
       <dep package="libxml2"/>
+      <dep package="libxslt"/>
       <dep package="itstool"/>
-      <dep package="python3"/>
     </dependencies>
+    <after>
+      <dep package="python3"/>
+    </after>
   </autotools>
 
   <autotools id="icu" autogen-sh="source/configure" autogenargs="--enable-rpath"