diff --git a/reftable/error.c b/reftable/error.c
index 93941f2145..0d1766735e 100644
--- a/reftable/error.c
+++ b/reftable/error.c
@@ -6,6 +6,7 @@ license that can be found in the LICENSE file or at
 https://developers.google.com/open-source/licenses/bsd
 */
 
+#include "system.h"
 #include "reftable-error.h"
 
 #include <stdio.h>
diff --git a/reftable/publicbasics.c b/reftable/publicbasics.c
index 0ad7d5c0ff..bcb82530d6 100644
--- a/reftable/publicbasics.c
+++ b/reftable/publicbasics.c
@@ -6,10 +6,10 @@ license that can be found in the LICENSE file or at
 https://developers.google.com/open-source/licenses/bsd
 */
 
+#include "system.h"
 #include "reftable-malloc.h"
 
 #include "basics.h"
-#include "system.h"
 
 static void *(*reftable_malloc_ptr)(size_t sz);
 static void *(*reftable_realloc_ptr)(void *, size_t);
diff --git a/reftable/tree.c b/reftable/tree.c
index b8899e060a..a5bf880985 100644
--- a/reftable/tree.c
+++ b/reftable/tree.c
@@ -6,10 +6,10 @@ license that can be found in the LICENSE file or at
 https://developers.google.com/open-source/licenses/bsd
 */
 
+#include "system.h"
 #include "tree.h"
 
 #include "basics.h"
-#include "system.h"
 
 struct tree_node *tree_search(void *key, struct tree_node **rootp,
 			      int (*compare)(const void *, const void *),
diff --git a/reftable/tree_test.c b/reftable/tree_test.c
index cbff125588..ac3a045ad4 100644
--- a/reftable/tree_test.c
+++ b/reftable/tree_test.c
@@ -6,6 +6,7 @@ license that can be found in the LICENSE file or at
 https://developers.google.com/open-source/licenses/bsd
 */
 
+#include "system.h"
 #include "tree.h"
 
 #include "basics.h"
diff --git a/t/helper/test-reftable.c b/t/helper/test-reftable.c
index 1f0a28cbb6..00237ef0d9 100644
--- a/t/helper/test-reftable.c
+++ b/t/helper/test-reftable.c
@@ -1,3 +1,4 @@
+#include "reftable/system.h"
 #include "reftable/reftable-tests.h"
 #include "test-tool.h"