diff --git a/compiler/capnpc-c.c b/compiler/capnpc-c.c
index b4d7df5..dfdc436 100644
--- a/compiler/capnpc-c.c
+++ b/compiler/capnpc-c.c
@@ -5,6 +5,7 @@
  * This software may be modified and distributed under the terms
  * of the MIT license.  See the LICENSE file for details.
  */
+#define _POSIX_C_SOURCE 200809L
 
 #include "schema.capnp.h"
 #include "str.h"
@@ -12,6 +13,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <ctype.h>
 
 struct value {
 	struct Type t;
diff --git a/lib/capn-malloc.c b/lib/capn-malloc.c
index 3290e79..569bef9 100644
--- a/lib/capn-malloc.c
+++ b/lib/capn-malloc.c
@@ -413,7 +413,7 @@ int64_t capn_size(struct capn *c)
 	size_t headersz, datasz = 0;
 	struct capn_ptr root;
 	struct capn_segment *seg;
-	int i;
+	uint32_t i;
 
 	if (c->segnum == 0)
 		return -1;
@@ -421,7 +421,7 @@ int64_t capn_size(struct capn *c)
 	root = capn_root(c);
 	seg = root.seg;
 
-    headersz = 8 * ((2 + c->segnum) / 2);
+	headersz = 8 * ((2 + c->segnum) / 2);
 
 	for (i = 0; i < c->segnum; i++, seg = seg->next) {
 		if (0 == seg)