kconfig: create directories needed for syncconfig by itself

'make syncconfig' creates some files such as include/config/auto.conf,
include/generate/autoconf.h, etc. but the necessary directory creation
relies on scripts/kconfig/Makefile.

To make Kconfig self-contained, create directories as needed in
conf_write_autoconf().

This change allows scripts/kconfig/Makefile cleanups; syncconfig can
be merged into simple-targets.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 88429d7..fad403d 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -899,6 +899,9 @@ static int conf_write_dep(const char *name)
 
 	fprintf(out, "\n$(deps_config): ;\n");
 	fclose(out);
+
+	if (make_parent_dir(name))
+		return 1;
 	rename("..config.tmp", name);
 	return 0;
 }
@@ -915,6 +918,8 @@ static int conf_split_config(void)
 	conf_read_simple(name, S_DEF_AUTO);
 	sym_calc_value(modules_sym);
 
+	if (make_parent_dir("include/config/foo.h"))
+		return 1;
 	if (chdir("include/config"))
 		return 1;
 
@@ -991,6 +996,7 @@ static int conf_split_config(void)
 				res = 1;
 				goto out;
 			}
+
 			/* Try it again. */
 			fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 			if (fd == -1) {
@@ -1063,14 +1069,22 @@ int conf_write_autoconf(void)
 	name = getenv("KCONFIG_AUTOHEADER");
 	if (!name)
 		name = "include/generated/autoconf.h";
+	if (make_parent_dir(name))
+		return 1;
 	if (rename(".tmpconfig.h", name))
 		return 1;
+
 	name = getenv("KCONFIG_TRISTATE");
 	if (!name)
 		name = "include/config/tristate.conf";
+	if (make_parent_dir(name))
+		return 1;
 	if (rename(".tmpconfig_tristate", name))
 		return 1;
+
 	name = conf_get_autoconfig_name();
+	if (make_parent_dir(name))
+		return 1;
 	/*
 	 * This must be the last step, kbuild has a dependency on auto.conf
 	 * and this marks the successful completion of the previous steps.