fix hint and gl2 build. NOTE: this does not change that GL2 segfaults right away. that is an issue that dates back at least 50 commits, but most likely even back to the webgl merge. I guess nobody actually tried to run hedgewars in GL2 since back then :P

//
// Prefix header for all source files of the 'CocoaTouchStaticLibrary' target in the 'CocoaTouchStaticLibrary' project.
//

#ifdef __OBJC__
    #import <Foundation/Foundation.h>
#endif