Remove zend_get_zendleng() declaration

Does not actually exist anywhere

Author: DanielEScherzer

UPGRADING.INTERNALS

@@ -45,6 +45,8 @@ PHP 8.5 INTERNALS UPGRADE NOTES
     properties.
   . ZEND_IS_XDIGIT() macro was removed because it was unused and its name
     did not match its actual behavior.
+  . zend_get_zendleng(), previously only declared when PHP was compiled with
+    ZTS support, was removed because it was unused, only forward declared.
   . zend_register_constant() now returns a pointer to the added constant
     on success and NULL on failure instead of SUCCESS/FAILURE.
 

Zend/zend_compile.h

@@ -886,7 +886,6 @@ ZEND_API zend_string *zend_get_compiled_variable_name(const zend_op_array *op_ar
 
 #ifdef ZTS
 const char *zend_get_zendtext(void);
-int zend_get_zendleng(void);
 #endif
 
 typedef zend_result (ZEND_FASTCALL *unary_op_type)(zval *, zval *);