diff --git a/ssl/encrypted_client_hello.cc b/ssl/encrypted_client_hello.cc
index 5344f7c..e288f3c 100644
--- a/ssl/encrypted_client_hello.cc
+++ b/ssl/encrypted_client_hello.cc
@@ -30,6 +30,7 @@
 
 #include "../crypto/bytestring/internal.h"
 #include "../crypto/internal.h"
+#include "../crypto/mem_internal.h"
 #include "internal.h"
 
 
diff --git a/ssl/ssl_cert.cc b/ssl/ssl_cert.cc
index 400a6da..d07dce5 100644
--- a/ssl/ssl_cert.cc
+++ b/ssl/ssl_cert.cc
@@ -32,6 +32,7 @@
 #include <openssl/x509.h>
 
 #include "../crypto/internal.h"
+#include "../crypto/mem_internal.h"
 #include "internal.h"
 
 
diff --git a/ssl/ssl_credential.cc b/ssl/ssl_credential.cc
index 6c23b52..e04482d 100644
--- a/ssl/ssl_credential.cc
+++ b/ssl/ssl_credential.cc
@@ -20,6 +20,7 @@
 #include <openssl/span.h>
 
 #include "../crypto/internal.h"
+#include "../crypto/mem_internal.h"
 #include "../crypto/spake2plus/internal.h"
 #include "internal.h"
 
diff --git a/tool/transport_common.cc b/tool/transport_common.cc
index 4a03834..f29b953 100644
--- a/tool/transport_common.cc
+++ b/tool/transport_common.cc
@@ -22,7 +22,9 @@
 
 #include <openssl/base.h>
 
+#include <optional>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <errno.h>