libyang CHANGE headers includes cleanup using include-what-you-use tool (#1098)

diff --git a/src/compat.c b/src/compat.c
index c877ceb..ca954f4 100644
--- a/src/compat.c
+++ b/src/compat.c
@@ -15,7 +15,8 @@
 #include "common.h"
 
 #include <string.h>
-#include <unistd.h>
+
+#include "config.h"
 
 #ifndef HAVE_STRNSTR
 char *