use usleep when possible, ./configure && make sure when you update

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@2722 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/include/switch_am_config.h.in

@@ -64,6 +64,9 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the `usleep' function. */
+#undef HAVE_USLEEP
+
 /* Define to 1 if you have the `vasprintf' function. */
 #undef HAVE_VASPRINTF
 

src/include/switch_utils.h

@@ -166,7 +166,11 @@ switch_mutex_unlock(obj->flag_mutex);
 /*!
   \brief Wait a desired number of microseconds and yield the CPU
 */
+#ifdef HAVE_USLEEP
+#define switch_yield(ms) usleep(ms);
+#else
 #define switch_yield(ms) apr_sleep(ms * 10); //apr_thread_yield();
+#endif
 
 /*!
   \brief Declares a function designed to set a dymaic global string