Sync src with amalgamated versions

Now src contains exactly what's embedded in mongoose.c and .h, nothing more.

Added `tools/amalgam.sh` to aamlgamate both files at once.

There are no functional changes to mongoose.c, .h in this PR, only slight filename changes.

test/test_util.c

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2014-2018 Cesanta Software Limited
+ * All rights reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the ""License"");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an ""AS IS"" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "test_util.h"
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifndef _WIN32
+#include <sys/time.h>
+#else
+#include <windows.h>
+#endif
+
+int num_tests = 0;
+
+static char *_escape(const char *s, size_t n) {
+  size_t i, j;
+  char *res = (char *) malloc(n * 4 + 1);
+  for (i = j = 0; s[i] != '\0' && i < n; i++) {
+    if (!iscntrl((int) s[i])) {
+      res[j++] = s[i];
+    } else {
+      j += sprintf(res + j, "\\x%02x", s[i]);
+    }
+  }
+  res[j] = '\0';
+  return res;
+}
+
+void _strfail(const char *a, const char *e, int len) {
+  char *ae, *ee;
+  if (len < 0) {
+    len = strlen(a);
+    if (strlen(e) > (size_t) len) len = strlen(e);
+  }
+  ae = _escape(a, len);
+  ee = _escape(e, len);
+  printf("Expected: %s\nActual  : %s\n", ee, ae);
+  free(ae);
+  free(ee);
+}
+
+int _assert_streq(const char *actual, const char *expected) {
+  if (strcmp(actual, expected) != 0) {
+    _strfail(actual, expected, -1);
+    return 0;
+  }
+  return 1;
+}
+
+int _assert_streq_nz(const char *actual, const char *expected) {
+  size_t n = strlen(expected);
+  if (strncmp(actual, expected, n) != 0) {
+    _strfail(actual, expected, n);
+    return 0;
+  }
+  return 1;
+}
+
+#if MG_ENABLE_POLL_UNTIL
+int c_str_ne(void *a, void *b) {
+  int r = strcmp((const char *) a, (const char *) b);
+  return r;
+}
+
+int c_int_ne(void *a, void *b) {
+  return *((int *) a) != (intptr_t) b;
+}
+
+int c_int_eq(void *a, void *b) {
+  return *((int *) a) == (intptr_t) b;
+}
+
+void poll_until(struct mg_mgr *mgr, double timeout, int (*cond)(void *, void *),
+                void *cond_arg1, void *cond_arg2) {
+  int i;
+  double start = cs_time();
+  while (cs_time() - start < timeout) {
+    mg_mgr_poll(mgr, 2);
+    if (cond != NULL && cond(cond_arg1, cond_arg2)) {
+      /* A few more cycles to test for overshoots. */
+      for (i = 0; i < 5; i++) {
+        mg_mgr_poll(mgr, 2);
+      }
+      return;
+    }
+  }
+}
+#endif