diff --git a/appl/popper/pop_dropcopy.c b/appl/popper/pop_dropcopy.c
index f4135c0c9..263e1b5b1 100644
--- a/appl/popper/pop_dropcopy.c
+++ b/appl/popper/pop_dropcopy.c
@@ -12,6 +12,7 @@ static char SccsId[] = "@(#)@(#)pop_dropcopy.c	2.6  2.6 4/3/91";
 #include <errno.h>
 #include <stdio.h>
 #include <sys/types.h>
+#include <unistd.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/file.h>
diff --git a/appl/popper/pop_updt.c b/appl/popper/pop_updt.c
index cada72817..2afa8e285 100644
--- a/appl/popper/pop_updt.c
+++ b/appl/popper/pop_updt.c
@@ -12,6 +12,7 @@ static char SccsId[] = "@(#)@(#)pop_updt.c	2.3  2.3 3/20/91";
 #include <errno.h>
 #include <stdio.h>
 #include <sys/types.h>
+#include <unistd.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/file.h>