Re: Unable to cross build for Windows

[Martin Dorey]

> in some MinGW64 header files?

Easily eliminated:

martind@sirius:~/tmp/svensson-2023-06-08$ cat make.c
#include <stdint.h>

intptr_t _get_osfhandle(int);
typedef void* HANDLE;

HANDLE fn() {
  return (HANDLE)_get_osfhandle(0);
}
martind@sirius:~/tmp/svensson-2023-06-08$ gcc -c -Wbad-function-cast make.c
make.c: In function ‘fn’:
make.c:7:10: warning: cast from function call of type ‘intptr_t {aka long int}’ 
to non-matching type ‘void *’ [-Wbad-function-cast]
   return (HANDLE)_get_osfhandle(0);
          ^
martind@sirius:~/tmp/svensson-2023-06-08$ 

That's gcc-6.3, but it's much the same in every version I tested from gcc-4.4 
to gcc-10.  A random version's man page, 
https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html, explains the 
flag as to:

> Warn when a function call is cast to a non-matching type. For example, warn 
> if a call to a function returning an integer type is cast to a pointer type.

I fear they mean exactly what they say there.  So, while you might call it a 
mistake, I don't think it's an accident.  
https://stackoverflow.com/a/35308713/18096 has some explanation of why it might 
sometimes be useful... and how it could be sidestepped by a change to Gnu Make, 
like our new friend wished for.