I updated and couldn't compile.
Here's the fix:
avoid compile error when <pthread.h> is absent
* src/internal.h (HAVE_PTHREAD_H): Test with "#ifdef", not "#if".
diff --git a/src/internal.h b/src/internal.h
index 6b2b633..6bed477 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -12,7 +12,7 @@
#include <sys/syslimits.h>
#endif
-#if HAVE_PTHREAD_H
+#ifdef HAVE_PTHREAD_H
#include <pthread.h>
#define PTHREAD_MUTEX_T(v) pthread_mutex_t v
#else
--
1.5.5.68.gd193e