Remove ability to declare userland case-insensitive constants

This is part of https://wiki.php.net/rfc/case_insensitive_constant_deprecation.

This commit only removes the ability to declare such constants from
userland. Before the functionality can be removed entirely, it's
necessary to figure out the handling of true/false/null first.

Author: nikic

UPGRADING

@@ -26,6 +26,8 @@ PHP 8.0 UPGRADE NOTES
   . Removed (unset) cast.
   . Removed track_errors ini directive. This means that $php_errormsg is no
     longer available. The error_get_last() function may be used instead.
+  . Removed the ability to define case-insensitive constants. The third
+    argument to define() may no longer be true.
   . Removed create_function(). Anonymous functions may be used instead.
   . Removed each(). foreach or ArrayIterator should be used instead.
 

Zend/tests/bug46304.phpt

@@ -6,9 +6,6 @@ Bug #46304 (defining namespaced constant using define())
 define('NS1\ns2\const1','value1');
 define('ns1\ns2\const2','value2');
 define('ns1\NS2\coNSt3','value3');
-define('NS1\ns2\const4','value4', true);
-define('ns1\ns2\const5','value5', true);
-define('ns1\NS2\coNSt6','value6', true);
 
 print NS1\ns2\const1 . "\n";
 print ns1\ns2\const1 . "\n";
@@ -22,29 +19,9 @@ print NS1\ns2\coNSt3 . "\n";
 print ns1\ns2\coNSt3 . "\n";
 print ns1\ns2\coNSt3 . "\n";
 
-print NS1\ns2\const4 . "\n";
-print ns1\ns2\const4 . "\n";
-print ns1\NS2\const4 . "\n";
-print ns1\ns2\coNSt4 . "\n";
-
-print NS1\ns2\const5 . "\n";
-print ns1\ns2\const5 . "\n";
-print ns1\NS2\const5 . "\n";
-print ns1\ns2\coNSt5 . "\n";
-
-print NS1\ns2\const6 . "\n";
-print ns1\ns2\const6 . "\n";
-print ns1\NS2\const6 . "\n";
-print ns1\ns2\coNSt6 . "\n";
-
 print NS1\ns2\coNSt1 . "\n";
 ?>
 --EXPECTF--
-Deprecated: define(): Declaration of case-insensitive constants is deprecated in %s on line 6
-
-Deprecated: define(): Declaration of case-insensitive constants is deprecated in %s on line 7
-
-Deprecated: define(): Declaration of case-insensitive constants is deprecated in %s on line 8
 value1
 value1
 value1
@@ -54,28 +31,6 @@ value2
 value3
 value3
 value3
-value4
-value4
-value4
-
-Deprecated: Case-insensitive constants are deprecated. The correct casing for this constant is "NS1\ns2\const4" in %s on line 25
-value4
-value5
-value5
-value5
-
-Deprecated: Case-insensitive constants are deprecated. The correct casing for this constant is "ns1\ns2\const5" in %s on line 30
-value5
-
-Deprecated: Case-insensitive constants are deprecated. The correct casing for this constant is "ns1\NS2\coNSt6" in %s on line 32
-value6
-
-Deprecated: Case-insensitive constants are deprecated. The correct casing for this constant is "ns1\NS2\coNSt6" in %s on line 33
-value6
-
-Deprecated: Case-insensitive constants are deprecated. The correct casing for this constant is "ns1\NS2\coNSt6" in %s on line 34
-value6
-value6
 
 Fatal error: Uncaught Error: Undefined constant 'NS1\ns2\coNSt1' in %sbug46304.php:%d
 Stack trace:

Zend/tests/case_insensitive_constant_deprecation.phpt

@@ -765,7 +765,6 @@ ZEND_FUNCTION(define)
 	zend_string *name;
 	zval *val, val_free;
 	zend_bool non_cs = 0;
-	int case_sensitive = CONST_CS;
 	zend_constant c;
 
 	ZEND_PARSE_PARAMETERS_START(2, 3)
@@ -775,15 +774,17 @@ ZEND_FUNCTION(define)
 		Z_PARAM_BOOL(non_cs)
 	ZEND_PARSE_PARAMETERS_END();
 
-	if (non_cs) {
-		case_sensitive = 0;
-	}
-
 	if (zend_memnstr(ZSTR_VAL(name), "::", sizeof("::") - 1, ZSTR_VAL(name) + ZSTR_LEN(name))) {
 		zend_error(E_WARNING, "Class constants cannot be defined or redefined");
 		RETURN_FALSE;
 	}
 
+	if (non_cs) {
+		zend_error(E_WARNING,
+			"define(): Declaration of case-insensitive constants is no longer supported");
+		RETURN_FALSE;
+	}
+
 	ZVAL_UNDEF(&val_free);
 
 repeat:
@@ -831,13 +832,8 @@ ZEND_FUNCTION(define)
 	zval_ptr_dtor(&val_free);
 
 register_constant:
-	if (non_cs) {
-		zend_error(E_DEPRECATED,
-			"define(): Declaration of case-insensitive constants is deprecated");
-	}
-
 	/* non persistent */
-	ZEND_CONSTANT_SET_FLAGS(&c, case_sensitive, PHP_USER_CONSTANT);
+	ZEND_CONSTANT_SET_FLAGS(&c, CONST_CS, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(name);
 	if (zend_register_constant(&c) == SUCCESS) {
 		RETURN_TRUE;