The existing name lookup code used C's toupper() function for
case-insensitive comparison. However, that function's result depends
on the current locale.
Since the matcher is supposed to match the likes of "iso-8859-1" and
"latin-1", matching may fail in locales, such as Turkish, where
toupper(i) is İ (or i, if the former isn't representable in the current
charset), but toupper(I) remains I, causing a False Negative.
To fix, use the US-ASCII-only QtMiscUtils::toAsciiLower() function,
which has the added advantage that it's inline.
Pick-to: 6.3 6.2
Change-Id: I70613c0167d84e3dc3d282c61c716b5dd0b3e6bb
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>