TC: int _chmod( const char *filename, int func [,int attrib] )

	- prototype in io.h, also include dos.h

	- if func = 0, returns access mode of file
	- if func = 1, sets access mode of file
	- attrib can be one of the following:

		    Turbo C	    MSC
		   FA_RDONLY	 _A_RDONLY
		   FA_HIDDEN	 _A_HIDDEN
		   FA_SYSTEM	 _A_SYSTEM


	- if func = 1,
	   returns 0 if OK
		  -1 with errno set to ENOENT or EACCES

	- if func = 0, returns MSDOS attribute