SL-10153: auto name{expression} declares an initializer_list

instead of a variable of type decltype(expression).

Using SHGetKnownFolderPath(FOLDERID_Fonts) in LLFontGL::getFontPathSystem()
requires new Windows #include files.

A variable with a constructor can't be declared within the braces of a switch
statement, even outside any of its case clauses.