added remaining functions, data structures, definitions required by http api to include/http

[Juan Lang]

> can you be more specific please?

Yes:

+#ifndef __HTTP_H__
+#define __HTTP_H__

Don't do that, it's already #ifdef protected.

+/*#if _WIN32_WINNT >= 0x0501*/

Dead code, just leave it out.

+typedef struct _HTTP_REQUEST_V2
+{
+    /* TODO : anonymous structure is not supported by C standard */
+    /* struct HTTP_REQUEST_V1; */

For one thing, that's what the DUMMYSTRUCTNAME macro is for.  For
another, by omitting it, you've made the structure binary incompatible
with the PSDK one for C code.  Clearly that's wrong.

I stopped reviewing here, you have many examples of the above error.

I'm also concerned whether this was the product of copy/paste, which
isn't allowed.  Was it?
--Juan