ext/date: make string pointers const

Author: MaxKellermann

ext/date/php_date.c

@@ -235,7 +235,7 @@ PHPAPI time_t php_time(void)
 
 #include "php_date_arginfo.h"
 
-static char* guess_timezone(const timelib_tzdb *tzdb);
+static const char* guess_timezone(const timelib_tzdb *tzdb);
 static void date_register_classes(void);
 /* }}} */
 
@@ -531,7 +531,7 @@ static PHP_INI_MH(OnUpdate_date_timezone)
 /* }}} */
 
 /* {{{ Helper functions */
-static char* guess_timezone(const timelib_tzdb *tzdb)
+static const char* guess_timezone(const timelib_tzdb *tzdb)
 {
 	/* Checking whether timezone has been set with date_default_timezone_set() */
 	if (DATEG(timezone) && (strlen(DATEG(timezone))) > 0) {
@@ -555,10 +555,9 @@ static char* guess_timezone(const timelib_tzdb *tzdb)
 
 PHPAPI timelib_tzinfo *get_timezone_info(void)
 {
-	char *tz;
 	timelib_tzinfo *tzi;
 
-	tz = guess_timezone(DATE_TIMEZONEDB);
+	const char *tz = guess_timezone(DATE_TIMEZONEDB);
 	tzi = php_date_parse_tzfile(tz, DATE_TIMEZONEDB);
 	if (! tzi) {
 		zend_throw_error(NULL, "Timezone database is corrupt. Please file a bug report as this should never happen");
@@ -589,7 +588,7 @@ static const char * const day_short_names[] = {
 	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 };
 
-static char *english_suffix(timelib_sll number)
+static const char *english_suffix(timelib_sll number)
 {
 	if (number >= 10 && number <= 19) {
 		return "th";
@@ -1649,7 +1648,7 @@ static const zend_object_iterator_funcs date_period_it_funcs = {
 	NULL, /* get_gc */
 };
 
-zend_object_iterator *date_object_period_get_iterator(zend_class_entry *ce, zval *object, int by_ref) /* {{{ */
+static zend_object_iterator *date_object_period_get_iterator(zend_class_entry *ce, zval *object, int by_ref) /* {{{ */
 {
 	date_period_it *iterator;
 
@@ -2011,7 +2010,7 @@ static void php_timezone_to_string(php_timezone_obj *tzobj, zval *zv)
 	}
 }
 
-void date_timezone_object_to_hash(php_timezone_obj *tzobj, HashTable *props)
+static void date_timezone_object_to_hash(php_timezone_obj *tzobj, HashTable *props)
 {
 	zval zv;