diff -Naur oiio-Release-1.2.1.orig/src/include/thread.h oiio-Release-1.2.1/src/include/thread.h
--- oiio-Release-1.2.1.orig/src/include/thread.h	2013-08-06 00:10:31.000000000 -0500
+++ oiio-Release-1.2.1/src/include/thread.h	2013-08-28 14:35:21.873905568 -0500
@@ -112,8 +112,10 @@
 #endif
 
 #if defined(__GNUC__) && (defined(_GLIBCXX_ATOMIC_BUILTINS) || (__GNUC__ * 100 + __GNUC_MINOR__ >= 401))
+#if !defined(__FreeBSD__) && !defined(__powerpc__) || defined(__x86_64__)
 #define USE_GCC_ATOMICS
 #endif
+#endif
 
 OIIO_NAMESPACE_ENTER
 {
@@ -227,6 +229,11 @@
 #elif defined(_MSC_VER)
     // Windows
     return _InterlockedExchangeAdd ((volatile LONG *)at, x);
+#elif defined (__powerpc__)
+    long long r;
+    r = *at;
+    *at += x;
+    return r;
 #else
 #   error No atomics on this platform.
 #endif
@@ -249,6 +256,11 @@
 #  else
     return InterlockedExchangeAdd64 ((volatile LONGLONG *)at, x);
 #  endif
+#elif defined (__powerpc__)
+   long long r;
+   r = *at;
+   *at += x;
+   return r;
 #else
 #   error No atomics on this platform.
 #endif
@@ -272,6 +284,8 @@
     return a->compare_and_swap (newval, compareval) == newval;
 #elif defined(_MSC_VER)
     return (_InterlockedCompareExchange ((volatile LONG *)at, newval, compareval) == compareval);
+#elif defined(__powerpc__)
+    return ((*at == compareval) ? (*at = newval), 1 : 0);
 #else
 #   error No atomics on this platform.
 #endif
@@ -289,6 +303,8 @@
     return a->compare_and_swap (newval, compareval) == newval;
 #elif defined(_MSC_VER)
     return (_InterlockedCompareExchange64 ((volatile LONGLONG *)at, newval, compareval) == compareval);
+#elif defined(__PPC__)
+    return ((*at == compareval) ? (*at = newval), 1 : 0);
 #else
 #   error No atomics on this platform.
 #endif