add initial CMake and Visual Studio build support

This moves the compatibility include files from include to
include/compat so we can use the awful MS C compiler
<../include/> trick to emulate the GNU #include_next extension.

This also removes a few old compat files we do not need anymore.

crypto/compat/posix_win.c

@@ -166,3 +166,27 @@ posix_setsockopt(int sockfd, int level, int optname,
 	int rc = setsockopt(sockfd, level, optname, (char *)optval, optlen);
 	return rc == 0 ? 0 : wsa_errno(WSAGetLastError());
 }
+
+#ifdef _MSC_VER
+int gettimeofday(struct timeval * tp, struct timezone * tzp)
+{
+	/*
+	 * Note: some broken versions only have 8 trailing zero's, the correct
+	 * epoch has 9 trailing zero's
+	 */
+	static const uint64_t EPOCH = ((uint64_t) 116444736000000000ULL);
+
+	SYSTEMTIME  system_time;
+	FILETIME    file_time;
+	uint64_t    time;
+
+	GetSystemTime(&system_time);
+	SystemTimeToFileTime(&system_time, &file_time);
+	time = ((uint64_t)file_time.dwLowDateTime);
+	time += ((uint64_t)file_time.dwHighDateTime) << 32;
+
+	tp->tv_sec = (long)((time - EPOCH) / 10000000L);
+	tp->tv_usec = (long)(system_time.wMilliseconds * 1000);
+	return 0;
+}
+#endif