check for header existance

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@4656 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/portaudio/configure.in

@@ -308,4 +308,7 @@ fi
 AC_SUBST(ENABLE_CXX_TRUE)
 AC_SUBST(ENABLE_CXX_FALSE)
 
+#check for some headers
+AC_CHECK_HEADERS([libkern/OSAtomic.h])
+
 AC_OUTPUT([Makefile portaudio-2.0.pc])

libs/portaudio/src/common/pa_ringbuffer.c

@@ -71,7 +71,7 @@
  *
  ****************/
 
-#if defined(__APPLE__) || defined(__FreeBSD__)
+#if defined(HAVE_LIBKERN_OSATOMIC_H) && defined(__APPLE__) || defined(__FreeBSD__)
 #   include <libkern/OSAtomic.h>
     /* Here are the memory barrier functions. Mac OS X and FreeBSD only provide
        full memory barriers, so the three types of barriers are the same. */