The ctype functions isspace(), isalnum(), et al take an integer
argument representing an unsigned character, or -1 for EOF. On
platforms with a signed char, it is unsafe to pass a char to them
without casting it to unsigned char first.
Most of git is already shielded against this by the ctype
implementation in git-compat-util.h, but xdiff, which uses libc
ctype.h, ought to be fixed.
Noticed-by: der Mouse <mouse@Rodents-Montreal.ORG> Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>