fixed build errors on Solaris

src/http_parser.cpp

@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <cctype>
 #include <algorithm>
+#include <stdlib.h>
 
 #include "libtorrent/config.hpp"
 #include "libtorrent/http_parser.hpp"
@@ -162,7 +163,7 @@ namespace libtorrent
 
 				if (name == "content-length")
 				{
-#ifdef WIN32
+#ifdef TORRENT_WINDOWS
 					m_content_length = _atoi64(value.c_str());
 #else
 					m_content_length = atoll(value.c_str());