diff --git a/lib/isc/include/isc/tm.h b/lib/isc/include/isc/tm.h
index 43e2aa34dd..44b81480e4 100644
--- a/lib/isc/include/isc/tm.h
+++ b/lib/isc/include/isc/tm.h
@@ -20,9 +20,12 @@
 /*! \file isc/tm.h
  * Provides portable conversion routines for struct tm.
  */
-
 #include <time.h>
 
+#include <isc/lang.h>
+#include <isc/types.h>
+
+
 ISC_LANG_BEGINDECLS
 
 time_t
diff --git a/lib/isc/tm.c b/lib/isc/tm.c
index 4f058a6c7c..c14d36d656 100644
--- a/lib/isc/tm.c
+++ b/lib/isc/tm.c
@@ -55,6 +55,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
+#include <ctype.h>
+
+#include <isc/tm.h>
 
 /*
  * Portable conversion routines for struct tm, replacing