apply changes from #4 to utils.h

Makefile

@@ -1,6 +1,6 @@
 GIT_SHA = $(shell git rev-parse --short HEAD)
 TARGET = brubeck
-LIBS = -lm -lpthread -lrt -lcrypto -ljansson
+LIBS = -lm -pthread -lrt -lcrypto -ljansson
 CC = gcc
 CXX = g++
 CFLAGS = -g -Wall -O3 -Wno-strict-aliasing -Isrc -Ivendor/ck/include -DNDEBUG=1 -DGIT_SHA=\"$(GIT_SHA)\"

src/utils.h

@@ -64,10 +64,23 @@ static inline void *xrealloc(void *ptr, size_t size)
 #define brubeck_atomic_fetch(P) __sync_add_and_fetch((P), 0)
 
 /* Compile read-write barrier */
-#define brubeck_barrier() __asm__ volatile("": : :"memory")
+#define brubeck_barrier() __sync_synchronize()
 
-/* Pause instruction to prevent excess processor bus usage */
+/* Pause instruction to prevent excess processor bus usage (when possible) */
+#if defined(__i386) || defined(__x86_64__)
 #define brubeck_cpu_relax() __asm__ volatile("pause\n": : :"memory")
+#elif defined(__powerpc__) || defined(__ppc__) || defined(__PPC__) \
+	|| defined(__powerpc64__) || defined(__ppc64__) || defined(__PPC64__)
+#define brubeck_cpu_relax() __asm__ volatile("or 27,27,27\n": : :"memory")
+#elif defined(__ARM_ARCH_6T2__) || defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
+	|| defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
+	|| defined(__ARM_ARCH_7S__) || defined(__aarch64__)
+#define brubeck_cpu_relax() __asm__ volatile("yield\n": : :"memory")
+#else
+/* Many OSes support it, but some require odd macros to get the declaration */
+int pthread_yield(void);
+#define brubeck_cpu_relax() pthread_yield ()
+#endif
 
 void initproctitle (int argc, char **argv);
 int getproctitle(char **procbuffer);