MDEV-21110 Unify turn_parser_debug_on() in sql_yacc.yy and sql_yacc_ora.yy

The block defining turn_parser_debug_on() now looks similar
in both sql_yacc.yy and sql_yacc_ora.yy.

sql/sql_parse.cc

@@ -7904,7 +7904,8 @@ void mysql_parse(THD *thd, char *rawbuf, uint length,
 {
   int error __attribute__((unused));
   DBUG_ENTER("mysql_parse");
-  DBUG_EXECUTE_IF("parser_debug", turn_parser_debug_on(););
+  DBUG_EXECUTE_IF("parser_debug", turn_parser_debug_on_MYSQLparse(););
+  DBUG_EXECUTE_IF("parser_debug", turn_parser_debug_on_ORAparse(););
 
   /*
     Warning.

sql/sql_priv.h

@@ -390,7 +390,8 @@ enum enum_yes_no_unknown
 
 /* sql_yacc.cc */
 #ifndef DBUG_OFF
-extern void turn_parser_debug_on();
+extern void turn_parser_debug_on_MYSQLparse();
+extern void turn_parser_debug_on_ORAparse();
 
 #endif
 

sql/sql_yacc.yy

@@ -153,7 +153,9 @@ static void yyerror(THD *thd, const char *s)
 
 
 #ifndef DBUG_OFF
-void turn_parser_debug_on()
+#define __CONCAT_UNDERSCORED(x,y)  x ## _ ## y
+#define _CONCAT_UNDERSCORED(x,y)   __CONCAT_UNDERSCORED(x,y)
+void _CONCAT_UNDERSCORED(turn_parser_debug_on,yyparse)()
 {
   /*
      MYSQLdebug is in sql/sql_yacc.cc, in bison generated code.

sql/sql_yacc_ora.yy

@@ -152,6 +152,31 @@ static void yyerror(THD *thd, const char *s)
 }
 
 
+#ifndef DBUG_OFF
+#define __CONCAT_UNDERSCORED(x,y)  x ## _ ## y
+#define _CONCAT_UNDERSCORED(x,y)   __CONCAT_UNDERSCORED(x,y)
+void _CONCAT_UNDERSCORED(turn_parser_debug_on,yyparse)()
+{
+  /*
+     MYSQLdebug is in sql/sql_yacc.cc, in bison generated code.
+     Turning this option on is **VERY** verbose, and should be
+     used when investigating a syntax error problem only.
+
+     The syntax to run with bison traces is as follows :
+     - Starting a server manually :
+       mysqld --debug-dbug="d,parser_debug" ...
+     - Running a test :
+       mysql-test-run.pl --mysqld="--debug-dbug=d,parser_debug" ...
+
+     The result will be in the process stderr (var/log/master.err)
+   */
+
+  extern int yydebug;
+  yydebug= 1;
+}
+#endif
+
+
 #define bincmp_collation(X,Y)           \
   do                                    \
   {                                     \