Fix 32-bit build.

__uint128_t and friends don't exist in 32-bit. (Build fix for
https://boringssl-review.googlesource.com/#/c/6975/.)

Change-Id: I959a1f23c8cb3f11344f1da50cecd82d3080e3a0
Reviewed-on: https://boringssl-review.googlesource.com/6983
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/internal.h b/crypto/internal.h
index 714f207..2229e19 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -188,7 +188,7 @@
 #endif
 
 
-#if !defined(_MSC_VER)
+#if !defined(_MSC_VER) && defined(OPENSSL_64_BIT)
 typedef __int128_t int128_t;
 typedef __uint128_t uint128_t;
 #endif