Isolated emscripten in new lib

lib/emscripten/emtests/test_mathfuncptr.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 <math.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  float (*fn)(float) = argc != 12 ? &sqrtf : &fabsf;
+  float (*fn2)(float) = argc != 13 ? &fabsf : &sqrtf;
+  float (*fn3)(float) = argc != 14 ? &erff : &fabsf;
+  printf("fn2(-5) = %d, fn(10) = %.2f, erf(10) = %.2f\n", (int)fn2(-5), fn(10),
+         fn3(10));
+  return 0;
+}