"SPINLOCK_NG" is x86-specific;
also, use __builtin_ia32_pause directly, as _mm_pause used to be inside target("sse") pragma until gcc 5.?
--- accelio-1.6/src/usr/linux/kernel.h.orig	2016-03-28 14:58:45.000000000 +0200
+++ accelio-1.6/src/usr/linux/kernel.h	2016-04-10 21:34:41.710405838 +0200
@@ -89,7 +89,9 @@
 
 typedef volatile int spinlock_t;
 
+#if defined(__i386__) || defined(__x86_64__)
 #define SPINLOCK_NG
+#endif
 
 #ifndef SPINLOCK_NG
 
@@ -146,7 +148,7 @@
 {
 	while (__sync_lock_test_and_set(spinlock, 1))
 		while (*spinlock)
-			_mm_pause();
+			__builtin_ia32_pause();
 }
 
 static inline int spin_try_lock(spinlock_t* spinlock)