Isolated emscripten in new lib

lib/emscripten/emtests/test_regex.c

@@ -0,0 +1,43 @@
+/*
+ * 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.
+ */
+
+// This is from// http://pic.dhe.ibm.com/infocenter/iseries/v7r1m0/index.jsp?topic=%2Frtref%2Fregexec.htm
+#include <regex.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) {
+  regex_t preg;
+  const char *string = "a very simple simple simple string";
+  const char *pattern = "\\(sim[a-z]le\\) \\1";
+  int rc;
+  size_t nmatch = 2;
+  regmatch_t pmatch[2];
+
+  if (0 != (rc = regcomp(&preg, pattern, 0))) {
+    printf("regcomp() failed, returning nonzero (%d)\n", rc);
+    exit(EXIT_FAILURE);
+  }
+
+  if (0 != (rc = regexec(&preg, string, nmatch, pmatch, 0))) {
+    printf("Failed to match '%s' with '%s',returning %d.\n", string, pattern,
+           rc);
+  } else {
+    printf(
+        "With the whole expression, "
+        "a matched substring \"%.*s\" is found at position %d to %d.\n",
+        pmatch[0].rm_eo - pmatch[0].rm_so, &string[pmatch[0].rm_so],
+        pmatch[0].rm_so, pmatch[0].rm_eo - 1);
+    printf(
+        "With the sub-expression, "
+        "a matched substring \"%.*s\" is found at position %d to %d.\n",
+        pmatch[1].rm_eo - pmatch[1].rm_so, &string[pmatch[1].rm_so],
+        pmatch[1].rm_so, pmatch[1].rm_eo - 1);
+  }
+  regfree(&preg);
+  return 0;
+}