diff --git a/appl/ftp/ftp/cmds.c b/appl/ftp/ftp/cmds.c
index bdc463850..443d866ad 100644
--- a/appl/ftp/ftp/cmds.c
+++ b/appl/ftp/ftp/cmds.c
@@ -435,7 +435,7 @@ mput(int argc, char **argv)
 					if (!*tp) {
 						tp = cp;
 						tp2 = tmpbuf;
-						while ((*tp2 = *tp) != NULL) {
+						while ((*tp2 = *tp) != '\0') {
 						     if (isupper(*tp2)) {
 						        *tp2 = 'a' + *tp2 - 'A';
 						     }
@@ -570,7 +570,7 @@ usage:
 		if (!*tp) {
 			tp = argv[2];
 			tp2 = tmpbuf;
-			while ((*tp2 = *tp) != NULL) {
+			while ((*tp2 = *tp) != '\0') {
 				if (isupper(*tp2)) {
 					*tp2 = 'a' + *tp2 - 'A';
 				}
diff --git a/appl/ftp/ftp/ftp_locl.h b/appl/ftp/ftp/ftp_locl.h
index 13977e9ad..84b9a342b 100644
--- a/appl/ftp/ftp/ftp_locl.h
+++ b/appl/ftp/ftp/ftp_locl.h
@@ -5,7 +5,17 @@
 #include <config.h>
 #endif
 
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
 #include <sys/param.h>
+#include <sys/time.h>
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
@@ -29,16 +39,6 @@
 
 extern int h_errno;
 
-#include <pwd.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <string.h>
-#include <time.h>
-#include <unistd.h>
-#include <netinet/in.h>
-
 #include "extern.h"
 #include "common.h"
 #include "ftp_var.h"
diff --git a/appl/ftp/ftpd/ftpd.c b/appl/ftp/ftpd/ftpd.c
index dd51ecc4d..a87a24cb4 100644
--- a/appl/ftp/ftpd/ftpd.c
+++ b/appl/ftp/ftpd/ftpd.c
@@ -45,6 +45,10 @@ RCSID("$Id$");
 #include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
+#include <sys/time.h>
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
 #include <sys/wait.h>
 
 #include <netinet/in.h>
@@ -851,7 +855,7 @@ filename_check(char *filename)
 	p++;
 	while(*p && (isalnum(*p) || strchr(good_chars, *p)))
 	    p++;
-	if(*p == NULL)
+	if(*p == '\0')
 	    return 0;
     }
     lreply(553, "\"%s\" is an illegal filename.", filename);
diff --git a/appl/popper/popper.c b/appl/popper/popper.c
index 187646266..d4e9bccc4 100644
--- a/appl/popper/popper.c
+++ b/appl/popper/popper.c
@@ -16,7 +16,7 @@ extern  state_table *   pop_get_command();
 int hangup = FALSE ;
 
 static RETSIGTYPE
-catchSIGHUP()
+catchSIGHUP(int sig)
 {
     hangup = TRUE ;
 
@@ -30,7 +30,7 @@ int     pop_timeout = POP_TIMEOUT;
 jmp_buf env;
 
 static RETSIGTYPE
-ring()
+ring(int sig)
 {
   longjmp(env,1);
 }