Add --disable-maintainer-mode; make bison optional

Also flex is now optional.

The outputs of flex and bison are now committed.  By default they get
built, but users who want to build from git can now

    ./configure --disable-maintainer-mode

to turn off the dependency on bison and flex.

Maintainers must, of course, commit the bison and/or flex outputs when
they make changes to parser.y and/or lexer.l, respectively.

parser.h

@@ -0,0 +1,190 @@
+/* A Bison parser, made by GNU Bison 3.0.2.  */
+
+/* Bison interface for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2013 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+#ifndef YY_YY_PARSER_H_INCLUDED
+# define YY_YY_PARSER_H_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+/* "%code requires" blocks.  */
+#line 10 "parser.y" /* yacc.c:1909  */
+
+#include "locfile.h"
+struct lexer_param;
+
+#define YYLTYPE location
+#define YYLLOC_DEFAULT(Loc, Rhs, N)             \
+  do {                                          \
+    if (N) {                                    \
+      (Loc).start = YYRHSLOC(Rhs, 1).start;     \
+      (Loc).end = YYRHSLOC(Rhs, N).end;         \
+    } else {                                    \
+      (Loc).start = YYRHSLOC(Rhs, 0).end;       \
+      (Loc).end = YYRHSLOC(Rhs, 0).end;         \
+    }                                           \
+  } while (0)
+ 
+
+#line 62 "parser.h" /* yacc.c:1909  */
+
+/* Token type.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    INVALID_CHARACTER = 258,
+    IDENT = 259,
+    FIELD = 260,
+    LITERAL = 261,
+    FORMAT = 262,
+    REC = 263,
+    SETMOD = 264,
+    EQ = 265,
+    NEQ = 266,
+    DEFINEDOR = 267,
+    AS = 268,
+    DEF = 269,
+    MODULE = 270,
+    IMPORT = 271,
+    IF = 272,
+    THEN = 273,
+    ELSE = 274,
+    ELSE_IF = 275,
+    REDUCE = 276,
+    FOREACH = 277,
+    END = 278,
+    AND = 279,
+    OR = 280,
+    TRY = 281,
+    CATCH = 282,
+    LABEL = 283,
+    BREAK = 284,
+    BREAK2 = 285,
+    BREAK3 = 286,
+    SETPIPE = 287,
+    SETPLUS = 288,
+    SETMINUS = 289,
+    SETMULT = 290,
+    SETDIV = 291,
+    SETDEFINEDOR = 292,
+    LESSEQ = 293,
+    GREATEREQ = 294,
+    QQSTRING_START = 295,
+    QQSTRING_TEXT = 296,
+    QQSTRING_INTERP_START = 297,
+    QQSTRING_INTERP_END = 298,
+    QQSTRING_END = 299
+  };
+#endif
+/* Tokens.  */
+#define INVALID_CHARACTER 258
+#define IDENT 259
+#define FIELD 260
+#define LITERAL 261
+#define FORMAT 262
+#define REC 263
+#define SETMOD 264
+#define EQ 265
+#define NEQ 266
+#define DEFINEDOR 267
+#define AS 268
+#define DEF 269
+#define MODULE 270
+#define IMPORT 271
+#define IF 272
+#define THEN 273
+#define ELSE 274
+#define ELSE_IF 275
+#define REDUCE 276
+#define FOREACH 277
+#define END 278
+#define AND 279
+#define OR 280
+#define TRY 281
+#define CATCH 282
+#define LABEL 283
+#define BREAK 284
+#define BREAK2 285
+#define BREAK3 286
+#define SETPIPE 287
+#define SETPLUS 288
+#define SETMINUS 289
+#define SETMULT 290
+#define SETDIV 291
+#define SETDEFINEDOR 292
+#define LESSEQ 293
+#define GREATEREQ 294
+#define QQSTRING_START 295
+#define QQSTRING_TEXT 296
+#define QQSTRING_INTERP_START 297
+#define QQSTRING_INTERP_END 298
+#define QQSTRING_END 299
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+typedef union YYSTYPE YYSTYPE;
+union YYSTYPE
+{
+#line 30 "parser.y" /* yacc.c:1909  */
+
+  jv literal;
+  block blk;
+
+#line 167 "parser.h" /* yacc.c:1909  */
+};
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+/* Location type.  */
+#if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
+typedef struct YYLTYPE YYLTYPE;
+struct YYLTYPE
+{
+  int first_line;
+  int first_column;
+  int last_line;
+  int last_column;
+};
+# define YYLTYPE_IS_DECLARED 1
+# define YYLTYPE_IS_TRIVIAL 1
+#endif
+
+
+
+int yyparse (block* answer, int* errors, struct locfile* locations, struct lexer_param* lexer_param_ptr);
+
+#endif /* !YY_YY_PARSER_H_INCLUDED  */