diff --git a/configure.ac b/configure.ac
index 2253d0d8..bb761523 100644
--- a/configure.ac
+++ b/configure.ac
@@ -72,9 +72,13 @@ AC_ARG_ENABLE(asm,
   enable_asm="yes"
 ])
 
-AS_IF([test "x$EMSCRIPTEN" != "x"],[
+AS_IF([test "x$EMSCRIPTEN" != "x"], [
   enable_asm="no"
-  AC_MSG_WARN([compiling to javascript - asm implementations disabled])
+  AC_MSG_WARN([compiling to JavaScript - asm implementations disabled])
+])
+AS_IF([test "$host_os" = "nacl" -o "$host_os" = "pnacl"], [
+  enable_asm="no"
+  AC_MSG_WARN([compiling to Native Client - asm implementations disabled])
 ])
 
 AC_ARG_ENABLE(pie,
diff --git a/src/libsodium/sodium/core.c b/src/libsodium/sodium/core.c
index 79004ef0..ad48bd20 100644
--- a/src/libsodium/sodium/core.c
+++ b/src/libsodium/sodium/core.c
@@ -106,7 +106,7 @@ _sodium_crit_leave(void)
     return 0;
 }
 
-#elif defined(__GNUC__) && !defined(__EMSCRIPTEN__)
+#elif defined(__GNUC__) && !defined(__EMSCRIPTEN__) && !defined(__native_client__)
 
 static volatile int _sodium_lock;