Revert fix for bug 76813 and re2c version bump

CentOS 7 ships with re2c 0.13.5 by default, so we should not have
bumped the required re2c version to 0.13.7.  However, 0.13.5 does not
support default rules, so we cannot use them to fix bug 76813.

This reverts commit 420184a and
5e15c9c.

Closes GH-6593.

Author: cmb69

NEWS

@@ -44,6 +44,9 @@ PHP                                                                        NEWS
     (david at bamsoftware, cmb)
   . Fixed bug #77565 (Incorrect locator detection in ZIP-based phars). (cmb)
 
+- Phpdbg:
+  . Reverted fix for bug #76813 (Access violation near NULL on source operand).
+    (cmb)
 
 07 Jan 2021, PHP 8.0.1
 

configure.ac

@@ -154,7 +154,7 @@ PHP_RUNPATH_SWITCH
 dnl Checks for some support/generator progs.
 PHP_PROG_AWK
 PHP_PROG_BISON([3.0.0])
-PHP_PROG_RE2C([0.13.7])
+PHP_PROG_RE2C([0.13.4])
 
 PHP_ARG_ENABLE([re2c-cgoto],
   [whether to enable computed goto gcc extension with re2c],

sapi/phpdbg/phpdbg_lexer.l

@@ -33,7 +33,7 @@ void phpdbg_init_lexer (phpdbg_param_t *stack, char *input) {
 
 	YYSETCONDITION(INITIAL);
 
-	LEX(text) = YYCURSOR = YYMARKER = (unsigned char *) input;
+	LEX(text) = YYCURSOR = (unsigned char *) input;
 	LEX(len) = strlen(input);
 }
 
@@ -165,10 +165,6 @@ INPUT       ("\\"[#"']|["]("\\\\"|"\\"["]|[^\n\000"])+["]|[']("\\"[']|"\\\\"|[^\
 	return T_ID;
 }
 
-<NORMAL>* {
-	return T_UNEXPECTED;
-}
-
 <RAW>{INPUT} {
 	phpdbg_init_param(yylval, STR_PARAM);
 	yylval->str = estrdup(yytext);

sapi/phpdbg/phpdbg_parser.y

@@ -63,13 +63,9 @@ ZEND_EXTERN_MODULE_GLOBALS(phpdbg)
 %% /* Rules */
 
 input
-	: non_empty_input { $$ = $1; }
-	| %empty
-	;
-
-non_empty_input
 	: command { $$ = $1; }
-	| non_empty_input T_SEPARATOR command { phpdbg_stack_separate($1.top); $$ = $3; }
+	| input T_SEPARATOR command { phpdbg_stack_separate($1.top); $$ = $3; }
+	| %empty
 	;
 
 command