Isolated emscripten in new lib

lib/emscripten/emtests/test_float32_precise.c

@@ -0,0 +1,26 @@
+/*
+ * 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) {
+  float x = 1.23456789123456789;
+  float y = 5.20456089123406709;
+  while (argc > 10 || argc % 19 == 15) {
+    // confuse optimizer
+    x /= y;
+    y = 2 * y - 1;
+    argc--;
+  }
+  x = x - y;
+  y = 3 * y - x / 2;
+  x = x * y;
+  y += 0.000000000123123123123;
+  x -= y / 7.654;
+  printf("\n%.20f, %.20f\n", x, y);
+  return 0;
+}