core: log_color - new global parameter to enable colorful log messages

- enabled only when log_stderr=1
- equivalent of -e command parameter
- it can be: 0 - disabled (no colors, default); 1 - enabled

cfg.lex

@@ -342,6 +342,7 @@ FORK_DELAY	fork_delay
 LOGSTDERROR	log_stderror
 LOGFACILITY	log_facility
 LOGNAME		log_name
+LOGCOLOR	log_color
 LISTEN		listen
 ADVERTISE	advertise|ADVERTISE
 ALIAS		alias
@@ -717,6 +718,7 @@ IMPORTFILE      "import_file"
 <INITIAL>{LOGSTDERROR}	{ yylval.strval=yytext; return LOGSTDERROR; }
 <INITIAL>{LOGFACILITY}	{ yylval.strval=yytext; return LOGFACILITY; }
 <INITIAL>{LOGNAME}	{ yylval.strval=yytext; return LOGNAME; }
+<INITIAL>{LOGCOLOR}	{ yylval.strval=yytext; return LOGCOLOR; }
 <INITIAL>{LISTEN}	{ count(); yylval.strval=yytext; return LISTEN; }
 <INITIAL>{ADVERTISE}	{ count(); yylval.strval=yytext; return ADVERTISE; }
 <INITIAL>{ALIAS}	{ count(); yylval.strval=yytext; return ALIAS; }

cfg.y

@@ -401,6 +401,7 @@ extern char *finame;
 %token LOGSTDERROR
 %token LOGFACILITY
 %token LOGNAME
+%token LOGCOLOR
 %token LISTEN
 %token ADVERTISE
 %token ALIAS
@@ -863,6 +864,8 @@ assign_stm:
 	| LOGFACILITY EQUAL error { yyerror("ID expected"); }
 	| LOGNAME EQUAL STRING { log_name=$3; }
 	| LOGNAME EQUAL error { yyerror("string value expected"); }
+	| LOGCOLOR EQUAL NUMBER { log_color=$3; }
+	| LOGCOLOR EQUAL error { yyerror("boolean value expected"); }
 	| DNS EQUAL NUMBER   { received_dns|= ($3)?DO_DNS:0; }
 	| DNS EQUAL error { yyerror("boolean value expected"); }
 	| REV_DNS EQUAL NUMBER { received_dns|= ($3)?DO_REV_DNS:0; }