kconfig: WERROR unmet symbol dependency

When KCONFIG_WERROR env variable is set treat unmet direct
symbol dependency as a terminal condition (error).

Suggested-by: Stefan Reinauer <[e-mail]>
Signed-off-by: Sergey Senozhatsky <[e-mail]>
Signed-off-by: Masahiro Yamada <[e-mail]>

scripts/kconfig/conf.c

···
 		break;
 	}
 
+	if (conf_errors())
+		exit(1);
+
 	if (sync_kconfig) {
 		name = getenv("KCONFIG_NOSILENTUPDATE");
 		if (name && *name) {
···
 	default:
 		break;
 	}
+
+	if (sym_dep_errors())
+		exit(1);
 
 	if (input_mode == savedefconfig) {
 		if (conf_write_defconfig(defconfig_file)) {

scripts/kconfig/confdata.c

···
 static const char *conf_filename;
 static int conf_lineno, conf_warnings;
 
+bool conf_errors(void)
+{
+	if (conf_warnings)
+		return getenv("KCONFIG_WERROR");
+	return false;
+}
+
 static void conf_warning(const char *fmt, ...)
 {
 	va_list ap;
···
 	char *p, *val;
 	struct symbol *sym;
 	int i, def_flags;
-	const char *warn_unknown, *werror, *sym_name;
+	const char *warn_unknown, *sym_name;
 
 	warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
-	werror = getenv("KCONFIG_WERROR");
 	if (name) {
 		in = zconf_fopen(name);
 	} else {
···
 	}
 	free(line);
 	fclose(in);
-
-	if (conf_warnings && werror)
-		exit(1);
 
 	return 0;
 }

scripts/kconfig/lkc_proto.h

···
 bool conf_get_changed(void);
 void conf_set_changed_callback(void (*fn)(void));
 void conf_set_message_callback(void (*fn)(const char *s));
+bool conf_errors(void);
 
 /* symbol.c */
 extern struct symbol * symbol_hash[SYMBOL_HASHSIZE];
···
 struct symbol ** sym_re_search(const char *pattern);
 const char * sym_type_name(enum symbol_type type);
 void sym_calc_value(struct symbol *sym);
+bool sym_dep_errors(void);
 enum symbol_type sym_get_type(struct symbol *sym);
 bool sym_tristate_within_range(struct symbol *sym,tristate tri);
 bool sym_set_tristate_value(struct symbol *sym,tristate tri);

scripts/kconfig/symbol.c

···
 
 struct symbol *modules_sym;
 static tristate modules_val;
+static int sym_warnings;
 
 enum symbol_type sym_get_type(struct symbol *sym)
 {
···
 			       "  Selected by [m]:\n");
 
 	fputs(str_get(&gs), stderr);
+	sym_warnings++;
+}
+
+bool sym_dep_errors(void)
+{
+	if (sym_warnings)
+		return getenv("KCONFIG_WERROR");
+	return false;
 }
 
 void sym_calc_value(struct symbol *sym)