config.h: fix hdr-check warnings

commit 8f7c7f5 ("config.c: add repo_config_set_worktree_gently()",
2018-12-27) adds three function declarations that cause the hdr-check
make target to complain. The hdr-check complaint is caused by placing
the new declarations, which include 'struct repository *' parameters,
before the declaration of 'struct repository'. Move the struct
declaration to the top of the file.

Signed-off-by: Ramsay Jones <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ramsay-jones

config.h

@@ -5,6 +5,7 @@
 #include "string-list.h"
 
 struct object_id;
+struct repository;
 
 /* git_config_parse_key() returns these negated: */
 #define CONFIG_INVALID_KEY 1
@@ -215,7 +216,6 @@ extern int git_configset_get_maybe_bool(struct config_set *cs, const char *key,
 extern int git_configset_get_pathname(struct config_set *cs, const char *key, const char **dest);
 
 /* Functions for reading a repository's config */
-struct repository;
 extern void repo_config(struct repository *repo, config_fn_t fn, void *data);
 extern int repo_config_get_value(struct repository *repo,
 				 const char *key, const char **value);