TC: int creattemp( char *filename, int attr )

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

	- creates new file (overwrites existing file) of filename with file
	  attribute attrib, for both read/write
	- attr consists of a combination of the following:

	  FA_RDONLY   set read only attribute
	  FA_HIDDEN   set hidden attribute
	  FA_SYSTEM   set system attribute

	- filename is a path name ending in a backslash (\); when file is
	  created, filename has a unique path name
	- file is created set to _fmode (O_TEXT or O_BINARY)
	- returns nonnegative integer if OK, else -1