configure.ac: define WINVER

Ensure that WINVER is defined early enough, so other system headers
won't fall back to their default value.  Specifically, this solves a
build failure (-Werror) with mingw-w64 ("WINVER redefined").

NEWS

@@ -1,5 +1,6 @@
 ver 0.16.6 (2010/??/??)
 * event_pipe: fix WIN32 regression
+* define WINVER in ./configure
 
 
 ver 0.16.5 (2010/10/09)

configure.ac

@@ -68,6 +68,7 @@ AC_CANONICAL_HOST
 
 case "$host_os" in
 mingw32* | windows*)
+	AM_CPPFLAGS="$AM_CPPFLAGS -DWINVER=0x0501"
 	MPD_LIBS="$MPD_LIBS -lws2_32"
 	;;
 esac

src/main_win32.c

@@ -27,7 +27,6 @@
 
 #include <glib.h>
 
-#define WINVER 0x0501
 #include <windows.h>
 
 static int service_argc;

src/server_socket.c

@@ -34,7 +34,6 @@
 #include <assert.h>
 
 #ifdef WIN32
-#define WINVER 0x0501
 #include <ws2tcpip.h>
 #include <winsock.h>
 #else

src/socket_util.c

@@ -28,7 +28,6 @@
 #include <sys/socket.h>
 #include <netdb.h>
 #else /* G_OS_WIN32 */
-#define WINVER 0x0501
 #include <ws2tcpip.h>
 #include <winsock.h>
 #endif /* G_OS_WIN32 */