diff --git a/src/pcm/pcm_local.h b/src/pcm/pcm_local.h
index 32e6dcdf..e4f65218 100644
--- a/src/pcm/pcm_local.h
+++ b/src/pcm/pcm_local.h
@@ -35,6 +35,7 @@
 #include "local.h"
 
 #ifdef THREAD_SAFE_API
+#define __USE_UNIX98 1	/* for old glibc */
 #include <pthread.h>
 #endif