Import byacc from invisible island, it brings us lots of compatibilities with

bison, keeping full compatibility with our previous yacc implementation.

Also bring the ability to create reentrant parser

This fix bin/140309 [1]

PR:		bin/140309 [1]
Submitted by:	Philippe Pepiot <ksh@philpep.org> [1]
Approved by:	des (mentor)
MFC after:	1 month

1 files changed, 25 insertions, 0 deletions

diff --git a/contrib/byacc/ACKNOWLEDGEMENTS b/contrib/byacc/ACKNOWLEDGEMENTS
new file mode 100644
index 000000000000..b66bb2506456
--- /dev/null
+++ b/contrib/byacc/ACKNOWLEDGEMENTS
@@ -0,0 +1,25 @@
+     Berkeley Yacc owes much to the unflagging efforts of Keith Bostic.
+His badgering kept me working on it long after I was ready to quit.
+
+     Berkeley Yacc is based on the excellent algorithm for computing LALR(1)
+lookaheads developed by Tom Pennello and Frank DeRemer.  The algorithm is
+described in their almost impenetrable article in TOPLAS 4,4.
+
+     Finally, much of the credit for the latest version must go to those
+who pointed out deficiencies of my earlier releases.  Among the most
+prolific contributors were
+
+	  Benson I. Margulies
+	  Dave Gentzel
+	  Antoine Verheijen
+	  Peter S. Housel
+	  Dale Smith
+	  Ozan Yigit
+	  John Campbell
+	  Bill Sommerfeld
+	  Paul Hilfinger
+	  Gary Bridgewater
+	  Dave Bakken
+	  Dan Lanciani
+	  Richard Sargent
+	  Parag Patel