Fix build with Bison 3.7 and newer (#2505)

docs/CONTRIBUTORS

@@ -53,6 +53,7 @@ Pieter Kapsenberg
 Piotr Binkowski
 Qingyao Sun
 Richard Myers
+Rupert Swarbrick
 Sean Cross
 Sebastien Van Cauwenberghe
 Sergi Granell

src/verilog.y

@@ -301,6 +301,15 @@ class AstSenTree;
 // Bison 3.0 and newer
 BISONPRE_VERSION(3.0,%define parse.error verbose)
 
+// We run bison with the -d argument. This tells it to generate a
+// header file with token names. Old versions of bison pasted the
+// contents of that file into the generated source as well; newer
+// versions just include it.
+//
+// Since we run bison through ../bisonpre, it doesn't know the correct
+// header file name, so we need to tell it.
+BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
+
 // When writing Bison patterns we use yTOKEN instead of "token",
 // so Bison will error out on unknown "token"s.