i18n: use UTF-8 string to lower filename for case collision check...
i18n: use UTF-8 string to lower filename for case collision check
Some character sets, cp932 (known as Shift-JIS for Japanese) for
example, use 0x41('A') - 0x5A('Z') and 0x61('a') - 0x7A('z') as second
or later character.
In such character set, case collision checking recognizes different
files as CASEFOLDED same file, if filenames are treated as byte
sequence.
win32mbcs extension is not appropriate to handle this problem, because
this problem can occur on other than Windows platform only if
problematic character set is used.
Callers of util.checkcase() use known ASCII filenames as last
component of path, and string.lower() is not applied to directory part
of path. So, util.checkcase() is kept intact, even though it applies
string.lower() to filenames.
