diff --git a/clients/fax500/rp500.c b/clients/fax500/rp500.c
index 6d5d955e06..daee4ccd3e 100644
--- a/clients/fax500/rp500.c
+++ b/clients/fax500/rp500.c
@@ -14,6 +14,7 @@
 
 #include <stdlib.h>
 
+#include <ac/ctype.h>
 #include <ac/signal.h>
 #include <ac/socket.h>
 #include <ac/string.h>
diff --git a/clients/mail500/main.c b/clients/mail500/main.c
index 7acc1d74d5..f405bd31bb 100644
--- a/clients/mail500/main.c
+++ b/clients/mail500/main.c
@@ -22,6 +22,8 @@
 #include <ac/wait.h>
 #include <ac/unistd.h>
 
+#include <sys/stat.h>
+
 #ifdef HAVE_SYS_PARAM_H
 #include <sys/param.h>
 #endif
diff --git a/clients/ud/util.c b/clients/ud/util.c
index caca219e63..dd1adf3f7f 100644
--- a/clients/ud/util.c
+++ b/clients/ud/util.c
@@ -14,6 +14,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <fcntl.h>
 
 #include <ac/ctype.h>
 #include <ac/errno.h>