[php-src] Issue #7867: FFI::cast vs FFI::memcpy

Issue: https://github.com/php/php-src/issues/7867 Comment Author: cmb69 There are issues regarding arrays and pointers of a certain type. While pointer arithmetic mostly works, it looses the alignment, e.g. ````.php $value = FFI::new('char[26]'); var_dump( FFI::alignof($value), // int(1) FFI::alignof($value + 0) // int(8) ); ```` But then there is the more serious issue, that casting from a pointer type to an array doesn't properly check the size of the types, e.g. ````.php $value = FFI::new('char[26]'); var_dump(FFI::cast('char[4]', $value + 0)); var_dump(FFI::cast('char[9]', $value + 0)); ```` outputs: ```` object(FFI\CData:char[4])#3 (4) { [0]=> string(1) "" [1]=> string(1) "" [2]=> string(1) "E" [3]=> string(1) "" } Fatal error: Uncaught FFI\Exception: attempt to cast to larger type in %s:5 ````