Fix incorrect architecture detection on Windows

code/qcommon/q_platform.h

@@ -97,10 +97,8 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #define ID_INLINE __inline
 #define PATH_SEP '\\'
 
-#if defined( __WIN64__ ) 
+#if defined(__x86_64__) || defined(_M_X64)
 #define ARCH_STRING "x86_64"
-#elif defined _M_ALPHA
-#define ARCH_STRING "AXP"
 #endif
 
 #define Q3_LITTLE_ENDIAN
@@ -126,8 +124,6 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 #if defined( _M_IX86 ) || defined( __i386__ )
 #define ARCH_STRING "x86"
-#elif defined _M_ALPHA
-#define ARCH_STRING "AXP"
 #endif
 
 #define Q3_LITTLE_ENDIAN