Added the DIAGNOSTICS_COLOR_WHEN var for controlling diagnostics-color.

Some IDEs do not work nicely with the recently added diagnostics-color
compiler switch. This patch adds the DIAGNOSTICS_COLOR_WHEN variable,
for controlling diagnostics-color switch. The default was chosen to be
'always', which makes the Arduino.mk file backwards compatible with
everything up to commit fa82c3a9db (Sat Sep 2 15:32:52 2017 +0100).

The supported values for DIAGNOSTICS_COLOR_WHEN are: `always`, `never`
and `auto`, and as with all Arduino.mk variables, it can easily be
overridden. For more details on the diagnostics-color compiler switch,
see: https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Language-Independent-Options.html#Language-Independent-Options

0 files changed, 0 insertions, 0 deletions