--- a/eratspeed.c
+++ b/eratspeed.c
@@ -1,6 +1,8 @@
 #define B32 1001
 #define B (B32 * 32)
 
+#include <stdio.h>
+#include <stdlib.h>
 #include "timing.h"
 #include "uint32.h"
 
--- a/primegaps.c
+++ b/primegaps.c
@@ -1,4 +1,5 @@
 #include <math.h>
+#include <stdio.h>
 #include "primegen.h"
 
 primegen pg;
--- a/primes.c
+++ b/primes.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include "primegen.h"
 #include "fs64.h"
 
--- a/primespeed.c
+++ b/primespeed.c
@@ -1,3 +1,5 @@
+#include <stdio.h>
+#include <stdlib.h>
 #include "timing.h"
 #include "primegen.h"
 #include "primegen_impl.h"
--- a/error.h
+++ b/error.h
@@ -1,7 +1,7 @@
 #ifndef ERROR_H
 #define ERROR_H
 
-extern int errno;
+#include <errno.h>
 
 extern int error_intr;
 extern int error_nomem;