Isolated emscripten in new lib

lib/emscripten/emtests/test_i64_precise_needed.c

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2016 The Emscripten Authors.  All rights reserved.
+ * Emscripten is available under two separate licenses, the MIT license and the
+ * University of Illinois/NCSA Open Source License.  Both these licenses can be
+ * found in the LICENSE file.
+ */
+
+#include <stdio.h>
+
+int main( int argc, char ** argv )
+{
+    unsigned long a = 0x60DD1695U;
+    unsigned long b = 0xCA8C4E7BU;
+    unsigned long long c = (unsigned long long)a * b;
+    printf( "c = %016llx\n", c );
+
+    return 0;
+}