From d73d5f8ee680a41bbd26d3944f4ae59f0239ebae Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Wed, 27 Dec 2017 00:10:18 +0100
Subject: [PATCH] Rather than checking for emscripten, perform a 128-bit mul

---
 configure.ac | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 479dc64f..923adfe1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -644,10 +644,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 #ifndef NATIVE_LITTLE_ENDIAN
 # error libsodium currently expects a little endian CPU for the 128-bit type
 #endif
-#ifdef __EMSCRIPTEN__
-# error emscripten currently supports only shift operations on integers \
-#       larger than 64 bits
-#endif
 #include <stddef.h>
 #include <stdint.h>
 #if defined(__SIZEOF_INT128__)
@@ -657,6 +653,8 @@ typedef unsigned uint128_t __attribute__((mode(TI)));
 #endif
 void fcontract(uint128_t *t) {
   *t += 0x8000000000000 - 1;
+  *t *= *t;
+  *t >>= 84;
 }
 ]], [[
 (void) fcontract;