reduce the size of Env by one pointer
(cherry picked from commit 83f5622545a2fc31eb7e7d5105f64ed6dd3058b3)
Change-Id: I5636290526d0165cfc61aee1e7a5b94db4a26cef
Fix segfault on infinite recursion in some cases
(cherry picked from commit bf1b294bd81ca76c5ec9fe3ecd52196bf52a8300)
Change-Id: Id137541426ec8536567835953fccf986a3aebf16
rl-next: Fix and support markdown frontmatter syntax
(cherry picked from commit 69b7876a0810269ad71807594cfd99b26cd8a5ff)
Change-Id: I8bfb8967af0943080fdd70d257c34abaf0a9fedf