diff --git a/cde/programs/dtcalc/calctool.c b/cde/programs/dtcalc/calctool.c
index 41d399b4c..b0d2ce9a8 100644
--- a/cde/programs/dtcalc/calctool.c
+++ b/cde/programs/dtcalc/calctool.c
@@ -416,7 +416,7 @@ char **argv ;
   srand48((long) time((time_t *) 0)) ;   /* Seed random number generator. */
 
   make_items() ;              /* Create server images and fir frames. */
-  if(v->display[0] == NULL)
+  if(v->display[0] == 0)
      do_clear() ;                /* Initialise and clear display. */
 
   if (v->rstate == TRUE)      /* Show the memory register window? */
@@ -941,7 +941,7 @@ init_vars()    /* Setup default values for various variables. */
   v->key_exp     = 0 ;            /* Not entering an exponent number. */
   v->pending_op  = 0 ;            /* No pending arithmetic operation. */
   v->titleline   = NULL ;         /* No User supplied title line. */
-  v->display[0]  = NULL ;         
+  v->display[0]  = 0 ;         
 
   v->x  = 0;
   v->x  = 0;
diff --git a/cde/programs/dtcalc/ds_common.c b/cde/programs/dtcalc/ds_common.c
index 7a51d65f2..9b1ec6844 100644
--- a/cde/programs/dtcalc/ds_common.c
+++ b/cde/programs/dtcalc/ds_common.c
@@ -33,6 +33,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include "ds_common.h"
 
 #define  FREE    (void) free