ERR: Fix build problems on Visual Studio 6

Source/cmStandardIncludes.h

@@ -118,6 +118,11 @@ extern int putenv (char *__string) __THROW;
 # endif
 #endif
 
+#ifdef _MSC_VER
+typedef unsigned short mode_t;
+#endif
+
+
 #ifdef CM_HAS_STD_BUT_NOT_FOR_IOSTREAM
 // some compilers have std:: but not for the stream library,
 // so we have to bring it into the std namespace by hand.

Source/cmSystemTools.cxx

@@ -35,6 +35,7 @@
 #include <string.h>
 #include <windows.h>
 #include <direct.h>
+#include <io.h>
 #define _unlink unlink
 #else
 #include <sys/types.h>