uintN_t is standard C99 type available in <stdint.h>, whereas u_intN_t
is defined <sys/types.h>
As upmpdcli already uses the uintN_t type, replace the few existing
u_intN_t types, as it breaks build with the musl C library, which is
very strict, because of the missing <sys/types.h>:
src/mediaserver/cdplugins/netfetch.h:71:5: error: ‘u_int64_t’ does not name a type
u_int64_t datacount() {
