ANSI escape sequences multiplatform (win10, linux)

[yalov]

Hello, It there a way to have colors set up as

trace and debug — full line gray (GRAY = "\033[90m"), not just from %^ to %$, but full line

info, warn, error, critical — full line white (normal), only the level tag is colored (default colors and a pattern se up as %^%l%$ are ok)

[tt4g]

Related #3103

wincolor_sink is already provided that uses the old Windows color output API.
However, wincolor_sink does not use ANSI escape sequences, so you can create a custom sink if you really want to use it.

See wiki: https://github.com/gabime/spdlog/wiki/4.-Sinks#implementing-your-own-sink

stdout_color_sink and stderr_color_sink, introduced in README.md, are aliases for ansicolor_sink and wincolor_sink.

spdlog/include/spdlog/sinks/stdout_color_sinks.h

Lines 14 to 27 in c3aed4b

	namespace spdlog {
	namespace sinks {
	#ifdef _WIN32
	using stdout_color_sink_mt = wincolor_stdout_sink_mt;
	using stdout_color_sink_st = wincolor_stdout_sink_st;
	using stderr_color_sink_mt = wincolor_stderr_sink_mt;
	using stderr_color_sink_st = wincolor_stderr_sink_st;
	#else
	using stdout_color_sink_mt = ansicolor_stdout_sink_mt;
	using stdout_color_sink_st = ansicolor_stdout_sink_st;
	using stderr_color_sink_mt = ansicolor_stderr_sink_mt;
	using stderr_color_sink_st = ansicolor_stderr_sink_st;
	#endif
	} // namespace sinks

[cschreib-ibex]

Unfortunately, the ANSI color sinks are not included in the static/shared library build of spdlog on Windows. The headers are there, but the implementation is missing, so trying to use these sinks results in a linker error. Looking at the source code, they should indeed work on Windows, so perhaps they should be included unconditionally in the build?

A workaround is to include both ansicolor_sink.h and ansicolor_sink-inl.h, but I don't know if this is advisable.

I have opened a new issue to cover this and other problems using this on Windows: #3138.