Add S_ISDIR compat define. From Patrick Spendrin.
diff --git a/src/compat.h b/src/compat.h
index cdc73b5..a6be8bb 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -54,4 +54,8 @@
 #endif
 #endif
 
+#ifndef S_ISDIR
+#define S_ISDIR(mode)	(((mode) & S_IFMT) == S_IFDIR)
+#endif
+
 #endif