*: check defined(_WIN32) instead of defined(WIN32)

Only _WIN32 is defined by the compiler, and WIN32 is not standardized
and may be missing.

Closes #169

src/net/Resolver.cxx

@@ -23,7 +23,7 @@
 
 #include <string>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <ws2tcpip.h>
 #else
 #include <sys/types.h>

src/net/SocketAddress.hxx

@@ -34,7 +34,7 @@
 
 #include <cstddef>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <winsock2.h>
 #else
 #include <sys/socket.h>
@@ -45,7 +45,7 @@
  */
 class SocketAddress {
 public:
-#ifdef WIN32
+#ifdef _WIN32
 	typedef int size_type;
 #else
 	typedef socklen_t size_type;

src/net/SocketError.cxx

@@ -23,7 +23,7 @@
 
 #include <string.h>
 
-#ifdef WIN32
+#ifdef _WIN32
 
 SocketErrorMessage::SocketErrorMessage(socket_error_t code) noexcept
 {

src/net/SocketError.hxx

@@ -23,7 +23,7 @@
 #include "Compiler.h"
 #include "system/Error.hxx"
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <winsock2.h>
 typedef DWORD socket_error_t;
 #else
@@ -35,7 +35,7 @@ gcc_pure
 static inline socket_error_t
 GetSocketError() noexcept
 {
-#ifdef WIN32
+#ifdef _WIN32
 	return WSAGetLastError();
 #else
 	return errno;
@@ -46,7 +46,7 @@ gcc_const
 static inline bool
 IsSocketErrorAgain(socket_error_t code) noexcept
 {
-#ifdef WIN32
+#ifdef _WIN32
 	return code == WSAEINPROGRESS;
 #else
 	return code == EAGAIN;
@@ -57,7 +57,7 @@ gcc_const
 static inline bool
 IsSocketErrorInterruped(socket_error_t code) noexcept
 {
-#ifdef WIN32
+#ifdef _WIN32
 	return code == WSAEINTR;
 #else
 	return code == EINTR;
@@ -68,7 +68,7 @@ gcc_const
 static inline bool
 IsSocketErrorClosed(socket_error_t code) noexcept
 {
-#ifdef WIN32
+#ifdef _WIN32
 	return code == WSAECONNRESET;
 #else
 	return code == EPIPE || code == ECONNRESET;
@@ -81,7 +81,7 @@ IsSocketErrorClosed(socket_error_t code) noexcept
  * and this class hosts the buffer.
  */
 class SocketErrorMessage {
-#ifdef WIN32
+#ifdef _WIN32
 	char msg[256];
 #else
 	const char *const msg;
@@ -99,7 +99,7 @@ gcc_const
 static inline std::system_error
 MakeSocketError(socket_error_t code, const char *msg) noexcept
 {
-#ifdef WIN32
+#ifdef _WIN32
 	return MakeLastError(code, msg);
 #else
 	return MakeErrno(code, msg);

src/net/ToString.cxx

@@ -34,7 +34,7 @@
 
 #include <algorithm>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <ws2tcpip.h>
 #else
 #include <netdb.h>