Issues with mingw-w64 gcc 10.2.0 on windows 10 about indicators

[p-ranav]

@mcmarius

The second issue encountered was the from_bytes conversion in function std::wstring utf8_decode(const std::string &str) from indicators/display_width.hpp

Can you describe the issue that was encountered?

[mcmarius]

It seems that std::wstring_convert::from_bytes does not like 4-byte characters on Windows with gcc and throws an exception:

terminate called after throwing an instance of 'std::range_error'
  what():  wstring_convert::from_bytes

It is called in the return statement of utf8_decode in indicators/display_width.hpp:285. It works fine on WSL now, but still throws an exception when compiling the demo with gcc MinGW. It works with 3-byte emojis such as ⌚️.
Replacing utf8_decode with the function in the linked SO answer seems to solve the issue.

With Terminus it works as expected, but there is another issue with 3-byte emojis using windows terminal which reproduces both on powershell profile and on wsl. This might be the fault of Windows Terminal though:

All emojis up to U+329x seem to exibit this behaviour (extra newlines), while emojis from U+1F00x seem to break on Windows without the mentioned fix (I picked some emojis randomly from this wikipedia article).