diff -up oiio-Release-1.1.10/src/include/thread.h.ppc oiio-Release-1.1.10/src/include/thread.h
--- oiio-Release-1.1.10/src/include/thread.h.ppc	2013-05-27 16:16:38.902025786 +0200
+++ oiio-Release-1.1.10/src/include/thread.h	2013-05-27 17:00:19.856167856 +0200
@@ -112,7 +112,7 @@ InterlockedExchangeAdd64 (volatile long
 #endif
 
 #if defined(__GNUC__) && (defined(_GLIBCXX_ATOMIC_BUILTINS) || (__GNUC__ * 100 + __GNUC_MINOR__ >= 401))
-#if !defined(__FreeBSD__) || defined(__x86_64__)
+#if !defined(__FreeBSD__) && !defined(__powerpc__) || defined(__x86_64__)
 #define USE_GCC_ATOMICS
 #endif
 #endif
@@ -235,6 +235,11 @@ atomic_exchange_and_add (volatile int *a
 #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
@@ -257,6 +262,11 @@ atomic_exchange_and_add (volatile long l
 #  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
@@ -280,6 +290,8 @@ atomic_compare_and_exchange (volatile in
     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
@@ -297,6 +309,8 @@ atomic_compare_and_exchange (volatile lo
     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