When working in a *nix environment, file names are case
sensitive. Although the internal charactersof the file
may need to be only upper-case (thus 'CASE UPPER'), the
handling of 'x Makefile' needs to protect the case of
the filename. Currently, before you can edit an
additional file that has a mixed case name, you have to
'CASE LOWER' before using 'x Makefile'.