drbd: split off drbd_config into separate file

To be more similar to what we do in the out-of-tree module and ease the
upstreaming process.

Signed-off-by: Christoph Böhmwalder <[e-mail]>
Reviewed-by: Joel Colledge <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/drbd/drbd_buildtag.c

···
 // SPDX-License-Identifier: GPL-2.0-only
-#include <linux/drbd.h>
+#include <linux/drbd_config.h>
 #include <linux/module.h>
 
 const char *drbd_buildtag(void)

drivers/block/drbd/drbd_int.h

···
 #include <linux/prefetch.h>
 #include <linux/drbd_genl_api.h>
 #include <linux/drbd.h>
+#include <linux/drbd_config.h>
 #include "drbd_strings.h"
 #include "drbd_state.h"
 #include "drbd_protocol.h"

include/linux/drbd.h

···
 
 #endif
 
-extern const char *drbd_buildtag(void);
-#define REL_VERSION "8.4.11"
-#define PRO_VERSION_MIN 86
-#define PRO_VERSION_MAX 101
-
-
 enum drbd_io_error_p {
 	EP_PASS_ON, /* FIXME should the better be named "Ignore"? */
 	EP_CALL_HELPER,

include/linux/drbd_config.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * drbd_config.h
+ * DRBD's compile time configuration.
+ */
+
+#ifndef DRBD_CONFIG_H
+#define DRBD_CONFIG_H
+
+extern const char *drbd_buildtag(void);
+
+#define REL_VERSION "8.4.11"
+#define PRO_VERSION_MIN 86
+#define PRO_VERSION_MAX 101
+
+#endif