Isolated emscripten in new lib

lib/emscripten/emtests/test_funcptr_namecollide.c

@@ -0,0 +1,31 @@
+/*
+ * 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>
+
+void do_call(void (*puts)(const char *), const char *str);
+
+void do_print(const char *str) {
+  if (!str) do_call(NULL, "delusion");
+  if ((int)str == -1) do_print(str + 10);
+  puts("====");
+  puts(str);
+  puts("====");
+}
+
+void do_call(void (*puts)(const char *), const char *str) {
+  if (!str) do_print("confusion");
+  if ((int)str == -1) do_call(NULL, str - 10);
+  (*puts)(str);
+}
+
+int main(int argc, char **argv) {
+  for (int i = 0; i < argc; i++) {
+    do_call(i != 10 ? do_print : NULL, i != 15 ? "waka waka" : NULL);
+  }
+  return 0;
+}