https://bugs.gentoo.org/722672#c4
--- a/src/syscall-x86_64.h
+++ b/src/syscall-x86_64.h
@@ -1,6 +1,16 @@
+#if ! defined(__ILP32__)
 #define __NR_io_setup		206
 #define __NR_io_destroy		207
 #define __NR_io_getevents	208
 #define __NR_io_submit		209
 #define __NR_io_cancel		210
 #define __NR_io_pgetevents	333
+#else
+#define __X32_SYSCALL_BIT       0x40000000
+#define __NR_io_setup		(__X32_SYSCALL_BIT + 543)
+#define __NR_io_destroy	(__X32_SYSCALL_BIT + 207)
+#define __NR_io_getevents	(__X32_SYSCALL_BIT + 208)
+#define __NR_io_submit		(__X32_SYSCALL_BIT + 544)
+#define __NR_io_cancel		(__X32_SYSCALL_BIT + 210)
+#define __NR_io_pgetevents	(__X32_SYSCALL_BIT + 333)
+#endif
--- a/src/io_pgetevents.c
+++ b/src/io_pgetevents.c
@@ -21,6 +21,7 @@
 #include <stdlib.h>
 #include <time.h>
 #include <signal.h>
+#include <stdint.h>
 #include "syscall.h"
 #include "aio_ring.h"
 
@@ -33,10 +34,17 @@
 		struct io_event *events, struct timespec *timeout,
 		sigset_t *sigmask)
 {
+#if (defined(__x86_64__) && ! defined(__ILP32__)) || ! defined(__x86_64__)
 	struct {
 		unsigned long ss;
 		unsigned long ss_len;
 	} data;
+#else
+	struct {
+		uint64_t ss;
+		uint64_t ss_len;
+	} data;
+#endif
 
 	if (aio_ring_is_empty(ctx, timeout))
 		return 0;