===================================================================
@@ -2460,7 +2460,10 @@ __gnat_number_of_cpus (void)
int cores = 1;
#if defined (linux) || defined (sun) || defined (AIX) \
- || (defined (__alpha__) && defined (_osf_)) || defined (__APPLE__)
+ || (defined (__alpha__) && defined (_osf_)) \
+ || (defined (__APPLE__) \
+ && defined (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) \
+ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050)
cores = (int) sysconf (_SC_NPROCESSORS_ONLN);
#elif (defined (__mips) && defined (__sgi))