Fix sbbs-windows build

BCC error filewrap.h 77: Multiple declaration for 'mode_t'

Introduced in commit e4adeee8

src/xpdev/filewrap.h

@@ -74,7 +74,9 @@
 #ifndef DISABLE_MKSTEMP_DEFINE
 	#define mkstemp(t)	_open(_mktemp(t), O_RDWR | O_CREAT | O_EXCL)
 #endif
+#if !defined(__BORLANDC__)
 	typedef short unsigned int mode_t;
+#endif
 
 #elif defined(__unix__)