diff --git a/setserial.c b/setserial.c
index fef6532..6a95513 100644
--- a/setserial.c
+++ b/setserial.c
@@ -11,10 +11,13 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <fcntl.h>
 #include <termios.h>
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
 
 #ifdef HAVE_ASM_IOCTLS_H
 #include <asm/ioctls.h>
@@ -714,7 +717,7 @@ fprintf(stderr, "\t* port\t\tset the I/O port\n");
 	exit(1);
 }
 
-main(int argc, char **argv)
+int main(int argc, char **argv)
 {
 	int	get_flag = 0, wild_intr_flag = 0;
 	int	c;