[Bug c++/77277] New: -fdiagnostics-color=always disabled on _WIN32 for no discernible reason

[bruck.michael at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77277

            Bug ID: 77277
           Summary: -fdiagnostics-color=always disabled on _WIN32 for no
                    discernible reason
           Product: gcc
           Version: 5.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bruck.michael at googlemail dot com
  Target Milestone: ---

diagnostic-color.c completely disables colorization for the _WIN32 platform. 

However both the most recent Windows 10 cmd.exe terminal as well as existing
terminal emulators available on older Windows versions fully support the Escape
sequences generated by gcc.

Proposal:
-fdiagnostics-color=always should always emit color codes

If isatty() is not reliable or unavailable on _WIN32 then should_colorize()
could be short-circuited to return false on _WIN32.