Complete eqn.7 parsing. Features all productions from the original 1975

CACM paper in an LR(1) parse (1 -> eqn_rewind()).  Right now the code is
a little jungly, but will clear up as I consolidate parse components.
The AST structure will also be cleaned up, as right now it's pretty ad
hoc (this won't change the parse itself).  I added the mandoc_strndup()
function will here.

1 files changed, 1 insertions, 0 deletions

diff --git a/libroff.h b/libroff.h
index 1cb2f534..3fa0e95a 100644
--- a/libroff.h
+++ b/libroff.h
@@ -46,6 +46,7 @@ struct	eqn_node {
 	struct eqn_def	 *defs;
 	size_t		  defsz;
 	char		 *data;
+	size_t		  rew;
 	size_t		  cur;
 	size_t		  sz;
 	struct eqn	  eqn;