kWordJoinerUTF8 utf8 character in stringrenderer.cpp is system encoding dependent

[vidiecan]

to make sure that c++ uses utf8 strings use either u8 prefix (C++11 support needed) or raw bytes e.g.,

static const char* kWordJoinerUTF8 = "\xE2\x81\xA0"; //u8"\u2060";