hedgewars-engine (rust): fix "protocol_version" -> "hedgewars_engine_protocol_version"
That function/symbol was renamed in ef2fc0210362
//
// Prefix header for all source files of the 'CocoaTouchStaticLibrary' target in the 'CocoaTouchStaticLibrary' project.
//
#ifdef __OBJC__
#import <Foundation/Foundation.h>
#endif