--- a/src/c-client/rfc822.c
+++ b/src/c-client/rfc822.c
@@ -37,6 +37,10 @@
 #include <time.h>
 #include "c-client.h"
 
+#ifdef __ANDROID__
+#define gethostid() (0L)
+#endif
+
 
 /* Support for deprecated features in earlier specifications.  Note that this
  * module follows RFC 2822, and all use of "rfc822" in function names is