Use unsigned char variable, or cast to (unsigned char), for
tolower()/islower() and friends. Fix compiler error
array subscript has type 'char' [-Werror=char-subscripts]
Signed-off-by: Manuel Bouyer <bouyer@netbsd.org>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Release-Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>