Contacts search is erroneously case-sensitive

[bam80]

I think Contacts search should be case-insensitive for sure.
It's not obvious if it's not, error-prone, confusing and has no point. No other apps have this search as case-sensitive.

I couldn't find some my contacts for a long time, until I realized occasionally it was because of the case.

[Viish]

Search in contacts fragment of linphone-android is already case insensitive.

[bam80]

I retested it and apparently the case in-sensitiveness is only spans for English names, indeed.
For e.g. Russian, it goes case-sensitive, still.

[Viish]

@julonexus What do you think?

[julonexus]

The main issue from insensitive search is that tolower (for example) doesn't work well with non wide characters (string / wstring).
liblinphone do the search on string so it can an issue.
On Desktop, we are using the insensitve search on QString (which is UTF16, so I guess it should not be an issue) for search contacts.
But results from smartsearchbar are done from liblinphone. It could be a good way to check on these results.

[bam80]

Is there any plan how to fix it?
Port liblinphone to wstring?