diff --git a/crypto/bn/internal.h b/crypto/bn/internal.h
index 72ef4e9..c8f0634 100644
--- a/crypto/bn/internal.h
+++ b/crypto/bn/internal.h
@@ -132,6 +132,8 @@
 #pragma intrinsic(__umulh, _umul128)
 #endif
 
+#include "../internal.h"
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
@@ -144,7 +146,7 @@
 
 #if !defined(_MSC_VER)
 /* MSVC doesn't support two-word integers on 64-bit. */
-#define BN_ULLONG	__uint128_t
+#define BN_ULLONG	uint128_t
 #endif
 
 #define BN_BITS2	64
diff --git a/crypto/ec/p224-64.c b/crypto/ec/p224-64.c
index e026fc4..8e93850 100644
--- a/crypto/ec/p224-64.c
+++ b/crypto/ec/p224-64.c
@@ -31,6 +31,7 @@
 #include <string.h>
 
 #include "internal.h"
+#include "../internal.h"
 
 
 typedef uint8_t u8;
@@ -50,7 +51,7 @@
  * to the unique minimal representation at the end of the computation. */
 
 typedef uint64_t limb;
-typedef __uint128_t widelimb;
+typedef uint128_t widelimb;
 
 typedef limb felem[4];
 typedef widelimb widefelem[7];
diff --git a/crypto/ec/p256-64.c b/crypto/ec/p256-64.c
index 3d7ace1..29e9a20 100644
--- a/crypto/ec/p256-64.c
+++ b/crypto/ec/p256-64.c
@@ -32,13 +32,12 @@
 #include <string.h>
 
 #include "internal.h"
+#include "../internal.h"
 
 
 typedef uint8_t u8;
 typedef uint64_t u64;
 typedef int64_t s64;
-typedef __uint128_t uint128_t;
-typedef __int128_t int128_t;
 
 /* The underlying field. P256 operates over GF(2^256-2^224+2^192+2^96-1). We
  * can serialise an element of this field into 32 bytes. We call this an
diff --git a/crypto/internal.h b/crypto/internal.h
index 5574aab..714f207 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -188,6 +188,12 @@
 #endif
 
 
+#if !defined(_MSC_VER)
+typedef __int128_t int128_t;
+typedef __uint128_t uint128_t;
+#endif
+
+
 /* Constant-time utility functions.
  *
  * The following methods return a bitmask of all ones (0xff...f) for true and 0
diff --git a/crypto/poly1305/poly1305_vec.c b/crypto/poly1305/poly1305_vec.c
index 4a826cc..1f5237d 100644
--- a/crypto/poly1305/poly1305_vec.c
+++ b/crypto/poly1305/poly1305_vec.c
@@ -34,7 +34,6 @@
 #define U64TO8_LE(m, v) (*(uint64_t *)(m)) = v
 
 typedef __m128i xmmi;
-typedef unsigned __int128 uint128_t;
 
 static const alignas(16) uint32_t poly1305_x64_sse2_message_mask[4] = {
     (1 << 26) - 1, 0, (1 << 26) - 1, 0};