Need <errno.h> for errno decl. on Solaris.

diff --git a/server/file.c b/server/file.c
index 3624fcb..2274fb6 100644
--- a/server/file.c
+++ b/server/file.c
@@ -8,6 +8,7 @@
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <errno.h>
 #include <sys/errno.h>
 #include <sys/stat.h>
 #include <sys/time.h>