Am I using PRIxPTR wrong? Musl-libc complains, glibc doesn't

[David Wuertele <dave+gmane@wuertele.com>]

/* test.c - demo difference between glibc and musl-libc wrt PRIxPTR
**
** Both native (x86_64 glibc) and target (arm musl-libc) define
** PRIxPTR as "lx", but uintptr_t as unsigned int:
**
**   $ gcc -E test.c | grep uintptr_t
**   typedef unsigned long int uintptr_t;
**     printf ("main is at 0x%""l" "x""\n", (uintptr_t) main);
**
**   $ arm-linux-musleabishf-gcc -E test.c | grep uintptr_t
**   typedef unsigned int uintptr_t;
**     printf ("main is at 0x%""lx""\n", (uintptr_t) main);
**
** While native gcc doesn't complain, target gcc does:
** 
**   $ gcc -c test.c -Wformat
**
**   $ arm-linux-musleabishf-gcc -c test.c -Wformat
**   test.c: In function ‘main’:
**   test.c:6:3: warning: format ‘%lx’ expects argument of type
** ‘long unsigned int’, but argument 2 has type ‘unsigned int’ [-Wformat]
*/

#include <stdio.h>
#include <inttypes.h>
int
main (int ac, char *av[])
{
  printf ("main is at 0x%"PRIxPTR"\n", (uintptr_t) main);
  return 0;
}