Revert this upstream commit which breaks a test case in "notmuch":

https://git.xapian.org/?p=xapian;a=commitdiff;h=5489fb2f838c0f0b0a593b4c17df282a93a1fe5a

See the notmuch FAQ entry:

https://notmuchmail.org/faq/#index12h2

This should be fixed for later releases.

diff --git a/backends/glass/glass_postlist.cc b/xapian-core/backends/glass/glass_postlist.cc
index 80e578b85..a47f14a68 100644
--- a/backends/glass/glass_postlist.cc
+++ b/backends/glass/glass_postlist.cc
@@ -759,7 +759,7 @@ GlassPostList::open_nearby_postlist(const std::string & term_,
     (void)need_pos;
     if (term_.empty())
 	RETURN(NULL);
-    if (!this_db.get() || this_db->postlist_table.is_modified())
+    if (!this_db.get() || this_db->postlist_table.is_writable())
 	RETURN(NULL);
     RETURN(new GlassPostList(this_db, term_, cursor->clone()));
 }