[php-src] Issue #7949: FFI struct with flexible array member

Issue: https://github.com/php/php-src/issues/7949 Comment Author: cmb69 There is actually support for flexible array members (and the struct hack char[0]), but the programmer is responsible to allocate a proper struct (FFI::new() can't do that). Assuming you have such a properly allocated struct, the following works: ```` $value->data[100] = "a"; var_dump($value->data[100]); // "a" ```` This is explicitly supported due to https://github.com/php/php-src/blob/655e578e816e6eec767b25963e93d8e044a9f392/ext/ffi/ffi.c#L1345 The fact that FFI::memcpy() does not work, looks like a bug to me. I think there should be an exception for ZEND_FFI_TYPE_ARRAY with type1->size == 0 at https://github.com/php/php-src/blob/655e578e816e6eec767b25963e93d8e044a9f392/ext/ffi/ffi.c#L4245