split stdout & stderr auto colouring

thus for some reason if one is connected to a tty and the other a file,
we still get colour in the tty by default.

in terms of options, --color and --no-color override both, no granular
ones added since it's not worth it imo.

this is backwards compatible with custom configs setting `_COLOR`.

it could be argued that setting $_COLOR to "false" for the auto non-tty
cases is redundant, which it is, but it doesn't hurt to do so; it ensures
that if anything (inc. 3rd-party hooks and such) rely on it that it
remains correct; and ensures that if anything in the future mistakenly
uses $_COLOR instead of $_COLOR_OUT|$_COLOR_ERR that at least that will
only be broken for the use case of only one of stdout|sdterr being a tty.

Gbp-Dch: Ignore

functions/arguments.sh

@@ -34,11 +34,15 @@ Arguments ()
 
 			--color)
 				_COLOR="true"
+				_COLOR_OUT="true"
+				_COLOR_ERR="true"
 				shift
 				;;
 
 			--no-color)
 				_COLOR="false"
+				_COLOR_OUT="false"
+				_COLOR_ERR="false"
 				shift
 				;;
 

functions/defaults.sh

@@ -296,10 +296,19 @@ Set_config_defaults ()
 	esac
 
 	# Setting live build options
-	if [ -t 1 ] && [ -t 2 ]; then
-		_COLOR="${_COLOR:-true}"
+	if [ -z "${_COLOR}" ]; then
+		_COLOR="auto"
+		_COLOR_OUT="true"
+		_COLOR_ERR="true"
+		if [ ! -t 1 ]; then
+			_COLOR_OUT="false"
+		fi
+		if [ ! -t 2 ]; then
+			_COLOR_ERR="false"
+		fi
 	else
-		_COLOR="${_COLOR:-false}"
+		_COLOR_OUT="${_COLOR}"
+		_COLOR_ERR="${_COLOR}"
 	fi
 	_BREAKPOINTS="${_BREAKPOINTS:-false}"
 	_DEBUG="${_DEBUG:-false}"

functions/echo.sh

@@ -34,7 +34,7 @@ Echo_error ()
 	shift
 
 	local PREFIX="${RED}E${NO_COLOR}"
-	if [ "${_COLOR}" = "false" ]; then
+	if [ "${_COLOR_ERR}" = "false" ]; then
 		PREFIX="E"
 	fi
 
@@ -49,7 +49,7 @@ Echo_message ()
 		shift
 
 		local PREFIX="${PURPLE}P${NO_COLOR}"
-		if [ "${_COLOR}" = "false" ]; then
+		if [ "${_COLOR_OUT}" = "false" ]; then
 			PREFIX="P"
 		fi
 
@@ -73,7 +73,7 @@ Echo_warning ()
 	shift
 
 	local PREFIX="${YELLOW}W${NO_COLOR}"
-	if [ "${_COLOR}" = "false" ]; then
+	if [ "${_COLOR_ERR}" = "false" ]; then
 		PREFIX="W"
 	fi