Make a new directory.
------------------------------------------------------------------------------

 Syntax

        GT_MkDir(<cDir>,[@<nError>]) --> lMade

 Arguments:

      <cDir> is the path of the directory to be made.

      <nError> is an optional parameter that must be passed by reference.
      If the directory creation fails the DOS error code will be placed in
      this variable.

 Returns:

      If the directory was made, GT_MkDir() returns true (.T.), if not it
      returns false (.F.).

 Description:

      GT_MkDir() can be used to make a new directory.

 Examples:

      // Make a new directory.

      nError := 0
      if !GT_MkDir("Knight",@nError)
         ? "Error =",nError
      endif

 Source: MKDIR.C

 Author:  Dave Pearson