v self: force the subprocess to show colors

cmd/tools/vself.v

@@ -7,6 +7,7 @@ fn main() {
 	vexe := pref.vexe_path()
 	vroot := os.dir(vexe)
 	os.chdir(vroot)
+	os.setenv('VCOLORS', 'always', true)
 
 	self_idx := os.args.index('self')
 	args := os.args[1..self_idx]

vlib/term/term.v

@@ -61,6 +61,10 @@ pub fn header(text, divider string) string {
 }
 
 fn supports_escape_sequences(fd int) bool {
+	vcolors_override := os.getenv('VCOLORS')
+	if vcolors_override == 'always' {
+		return true
+	}    
 	$if windows {
 		return (is_atty(fd) & 0x0004) > 0 && os.getenv('TERM') != 'dumb' // ENABLE_VIRTUAL_TERMINAL_PROCESSING
 	} $else {