refactor: Use 'bool' type for many internal flags

They were 'int' type variables that should be modernized to use 'bool'.
Also limit variable scope if they are used in only one file.

src/flexdef.h

@@ -455,7 +455,7 @@ extern struct env_bundle_t env;
  * reject_really_used - same for REJECT
   */
 
-extern int syntaxerror, eofseen;
+extern bool syntaxerror, eofseen;
 extern int yymore_used, reject, real_reject, continued_action, in_rule;
 
 /* Variables used in the flex input routines:
@@ -568,7 +568,7 @@ extern int current_state_type;
 /* True if the input rules include a rule with both variable-length head
  * and trailing context, false otherwise.
  */
-extern int variable_trailing_context_rules;
+extern bool variable_trailing_context_rules;
 
 
 /* Variables for protos:
@@ -945,7 +945,7 @@ extern int copysingl(int, int);
 extern void dumpnfa(int);
 
 /* Finish up the processing for a rule. */
-extern void finish_rule(int, int, int, int, int);
+extern void finish_rule(int, bool, int, int, int);
 
 /* Connect two machines together. */
 extern int link_machines(int, int);

src/main.c

@@ -47,7 +47,7 @@ void readin(void);
 void set_up_initial_allocations(void);
 
 /* these globals are all defined and commented in flexdef.h */
-int     syntaxerror, eofseen;
+bool    syntaxerror, eofseen;
 int     yymore_used, reject, real_reject, continued_action, in_rule;
 int     datapos, dataline, linenum;
 FILE   *skelfile = NULL;
@@ -65,7 +65,7 @@ int    *firstst, *lastst, *finalst, *transchar, *trans1, *trans2;
 int    *accptnum, *assoc_rule, *state_type;
 int    *rule_type, *rule_linenum, *rule_useful;
 int     current_state_type;
-int     variable_trailing_context_rules;
+bool    variable_trailing_context_rules;
 int     numtemps, numprots, protprev[MSP], protnext[MSP], prottbl[MSP];
 int     protcomst[MSP], firstprot, lastprot, protsave[PROT_SAVE_SIZE];
 int     numecs, nextecm[CSIZE + 1], ecgroup[CSIZE + 1], nummecs,
@@ -1166,7 +1166,8 @@ void flexinit (int argc, char **argv)
 	numas = numsnpairs = tmpuses = 0;
 	numecs = numeps = eps2 = num_reallocs = hshcol = dfaeql = totnst =
 	    0;
-	numuniq = numdup = hshsave = eofseen = datapos = dataline = 0;
+	numuniq = numdup = hshsave = datapos = dataline = 0;
+	eofseen = false;
 	num_backing_up = onesp = numprots = 0;
 	variable_trailing_context_rules = bol_needed = false;
 

src/nfa.c

@@ -191,7 +191,7 @@ int     dupmachine (int mach)
  * context has variable length.
  */
 
-void    finish_rule (int mach, int variable_trail_rule, int headcnt, int trailcnt,
+void    finish_rule (int mach, bool variable_trail_rule, int headcnt, int trailcnt,
 		     int pcont_act)
 {
 	char    action_text[MAXLINE];

src/parse.y

@@ -68,7 +68,9 @@
 #include "tables.h"
 
 int pat, scnum, eps, headcnt, trailcnt, lastchar, i, rulelen;
-int trlcontxt, xcluflg, currccl, cclsorted, varlength, variable_trail_rule;
+static int currccl;
+bool trlcontxt;
+static bool xcluflg, cclsorted, varlength, variable_trail_rule;
 
 int *scon_stk;
 int scon_stk_ptr;

src/scan.l

@@ -40,7 +40,7 @@
 
 #include "parse.h"
 extern bool tablesverify, tablesext;
-extern int trlcontxt; /* Set in  parse.y for each rule. */
+extern bool trlcontxt; /* Set in parse.y for each rule. */
 extern const char *escaped_qstart, *escaped_qend;
 
 #define M4QSTART "[""["
@@ -155,10 +155,10 @@ void context_member(char *, const char *);
 %}
 %%
 	static int bracelevel, didadef, indented_code;
-	static int doing_rule_action = false;
-	static int option_sense;
+	static bool doing_rule_action = false;
+	static bool option_sense;
 
-	int doing_codeblock = false;
+	static bool doing_codeblock = false;
 	int brace_depth=0, brace_start_line=0;
 	char nmdef[MAXLINE];
 
@@ -395,7 +395,7 @@ void context_member(char *, const char *);
 	main		{
 			ctrl.do_main = option_sense;
 			/* Override yywrap */
-			if( option_sense == true )
+			if (option_sense)
                 		ctrl.do_yywrap = false;
 			}
 	meta-ecs	ctrl.usemecs = option_sense;
@@ -471,7 +471,7 @@ void context_member(char *, const char *);
 	tables-file         return TOK_TABLES_FILE;
 	tables-verify   {
                     tablesverify = option_sense;
-                    if(!tablesext && option_sense)
+                    if (!tablesext && option_sense)
                         tablesext = true;
                     }
 

src/yylex.c

@@ -51,7 +51,7 @@ int     yylex (void)
 		toktype = flexscan ();
         }
 	if (toktype == EOF || toktype == 0) {
-		eofseen = 1;
+		eofseen = true;
 
 		if (sectnum == 1) {
 			synerr (_("premature EOF"));