Remove extern from function declared in headers. (#13790)

By default functions are declared as extern in C/C++ headers. The goal
of this PR is to reduce the wall of text that many headers have and,
more importantly, to make the declaration of extern'd variables - of
which we have many dispersed in various places - easily and quickly
identifiable.

Automatically generated with:

    $ git grep -l '^extern.*(' '**.h' | \
            grep -v libjudy | \
            grep -v 'sqlite3.h' | \
            xargs sed -i -e 's/extern \(.*(.*$\)/\1/'

This is a NFC.

5 files changed, 45 insertions, 45 deletions

diff --git a/registry/registry.h b/registry/registry.h
index 5e274487da..6aa3f0a118 100644
--- a/registry/registry.h
+++ b/registry/registry.h
@@ -55,29 +55,29 @@
 
 // initialize the registry
 // should only happen when netdata starts
-extern int registry_init(void);
+int registry_init(void);
 
 // free all data held by the registry
 // should only happen when netdata exits
-extern void registry_free(void);
+void registry_free(void);
 
 // HTTP requests handled by the registry
-extern int registry_request_access_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *name, time_t when);
-extern int registry_request_delete_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *delete_url, time_t when);
-extern int registry_request_search_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *request_machine, time_t when);
-extern int registry_request_switch_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *new_person_guid, time_t when);
-extern int registry_request_hello_json(RRDHOST *host, struct web_client *w);
+int registry_request_access_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *name, time_t when);
+int registry_request_delete_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *delete_url, time_t when);
+int registry_request_search_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *request_machine, time_t when);
+int registry_request_switch_json(RRDHOST *host, struct web_client *w, char *person_guid, char *machine_guid, char *url, char *new_person_guid, time_t when);
+int registry_request_hello_json(RRDHOST *host, struct web_client *w);
 
 // update the registry config
-extern void registry_update_cloud_base_url();
+void registry_update_cloud_base_url();
 
 // update the registry monitoring charts
-extern void registry_statistics(void);
+void registry_statistics(void);
 
-extern char *registry_get_this_machine_guid(void);
-extern char *registry_get_mgmt_api_key(void);
-extern char *registry_get_this_machine_hostname(void);
+char *registry_get_this_machine_guid(void);
+char *registry_get_mgmt_api_key(void);
+char *registry_get_this_machine_hostname(void);
 
-extern int regenerate_guid(const char *guid, char *result);
+int regenerate_guid(const char *guid, char *result);
 
 #endif /* NETDATA_REGISTRY_H */
diff --git a/registry/registry_internals.h b/registry/registry_internals.h
index a49b4a4c3d..3456d788d7 100644
--- a/registry/registry_internals.h
+++ b/registry/registry_internals.h
@@ -71,20 +71,20 @@ struct registry {
 extern struct registry registry;
 
 // REGISTRY LOW-LEVEL REQUESTS (in registry-internals.c)
-extern REGISTRY_PERSON *registry_request_access(char *person_guid, char *machine_guid, char *url, char *name, time_t when);
-extern REGISTRY_PERSON *registry_request_delete(char *person_guid, char *machine_guid, char *url, char *delete_url, time_t when);
-extern REGISTRY_MACHINE *registry_request_machine(char *person_guid, char *machine_guid, char *url, char *request_machine, time_t when);
+REGISTRY_PERSON *registry_request_access(char *person_guid, char *machine_guid, char *url, char *name, time_t when);
+REGISTRY_PERSON *registry_request_delete(char *person_guid, char *machine_guid, char *url, char *delete_url, time_t when);
+REGISTRY_MACHINE *registry_request_machine(char *person_guid, char *machine_guid, char *url, char *request_machine, time_t when);
 
 // REGISTRY LOG (in registry_log.c)
-extern void registry_log(char action, REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name);
-extern int registry_log_open(void);
-extern void registry_log_close(void);
-extern void registry_log_recreate(void);
-extern ssize_t registry_log_load(void);
+void registry_log(char action, REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name);
+int registry_log_open(void);
+void registry_log_close(void);
+void registry_log_recreate(void);
+ssize_t registry_log_load(void);
 
 // REGISTRY DB (in registry_db.c)
-extern int registry_db_save(void);
-extern size_t registry_db_load(void);
-extern int registry_db_should_be_saved(void);
+int registry_db_save(void);
+size_t registry_db_load(void);
+int registry_db_should_be_saved(void);
 
 #endif //NETDATA_REGISTRY_INTERNALS_H_H
diff --git a/registry/registry_machine.h b/registry/registry_machine.h
index 77ab5aaf51..bc95ecf699 100644
--- a/registry/registry_machine.h
+++ b/registry/registry_machine.h
@@ -34,10 +34,10 @@ struct registry_machine {
 };
 typedef struct registry_machine REGISTRY_MACHINE;
 
-extern REGISTRY_MACHINE *registry_machine_find(const char *machine_guid);
-extern REGISTRY_MACHINE_URL *registry_machine_url_allocate(REGISTRY_MACHINE *m, REGISTRY_URL *u, time_t when);
-extern REGISTRY_MACHINE *registry_machine_allocate(const char *machine_guid, time_t when);
-extern REGISTRY_MACHINE *registry_machine_get(const char *machine_guid, time_t when);
-extern REGISTRY_MACHINE_URL *registry_machine_link_to_url(REGISTRY_MACHINE *m, REGISTRY_URL *u, time_t when);
+REGISTRY_MACHINE *registry_machine_find(const char *machine_guid);
+REGISTRY_MACHINE_URL *registry_machine_url_allocate(REGISTRY_MACHINE *m, REGISTRY_URL *u, time_t when);
+REGISTRY_MACHINE *registry_machine_allocate(const char *machine_guid, time_t when);
+REGISTRY_MACHINE *registry_machine_get(const char *machine_guid, time_t when);
+REGISTRY_MACHINE_URL *registry_machine_link_to_url(REGISTRY_MACHINE *m, REGISTRY_URL *u, time_t when);
 
 #endif //NETDATA_REGISTRY_MACHINE_H
diff --git a/registry/registry_person.h b/registry/registry_person.h
index 556c426f77..674596be6b 100644
--- a/registry/registry_person.h
+++ b/registry/registry_person.h
@@ -42,20 +42,20 @@ struct registry_person {
 typedef struct registry_person REGISTRY_PERSON;
 
 // PERSON_URL
-extern REGISTRY_PERSON_URL *registry_person_url_index_find(REGISTRY_PERSON *p, const char *url);
-extern REGISTRY_PERSON_URL *registry_person_url_index_add(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu) NEVERNULL WARNUNUSED;
-extern REGISTRY_PERSON_URL *registry_person_url_index_del(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu) WARNUNUSED;
+REGISTRY_PERSON_URL *registry_person_url_index_find(REGISTRY_PERSON *p, const char *url);
+REGISTRY_PERSON_URL *registry_person_url_index_add(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu) NEVERNULL WARNUNUSED;
+REGISTRY_PERSON_URL *registry_person_url_index_del(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu) WARNUNUSED;
 
-extern REGISTRY_PERSON_URL *registry_person_url_allocate(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when);
-extern REGISTRY_PERSON_URL *registry_person_url_reallocate(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when, REGISTRY_PERSON_URL *pu);
+REGISTRY_PERSON_URL *registry_person_url_allocate(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when);
+REGISTRY_PERSON_URL *registry_person_url_reallocate(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when, REGISTRY_PERSON_URL *pu);
 
 // PERSON
-extern REGISTRY_PERSON *registry_person_find(const char *person_guid);
-extern REGISTRY_PERSON *registry_person_allocate(const char *person_guid, time_t when);
-extern REGISTRY_PERSON *registry_person_get(const char *person_guid, time_t when);
+REGISTRY_PERSON *registry_person_find(const char *person_guid);
+REGISTRY_PERSON *registry_person_allocate(const char *person_guid, time_t when);
+REGISTRY_PERSON *registry_person_get(const char *person_guid, time_t when);
 
 // LINKING PERSON -> PERSON_URL
-extern REGISTRY_PERSON_URL *registry_person_link_to_url(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when);
-extern void registry_person_unlink_from_url(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu);
+REGISTRY_PERSON_URL *registry_person_link_to_url(REGISTRY_PERSON *p, REGISTRY_MACHINE *m, REGISTRY_URL *u, char *name, size_t namelen, time_t when);
+void registry_person_unlink_from_url(REGISTRY_PERSON *p, REGISTRY_PERSON_URL *pu);
 
 #endif //NETDATA_REGISTRY_PERSON_H
diff --git a/registry/registry_url.h b/registry/registry_url.h
index 0cc364fdfe..8ba0391bc3 100644
--- a/registry/registry_url.h
+++ b/registry/registry_url.h
@@ -23,13 +23,13 @@ struct registry_url {
 typedef struct registry_url REGISTRY_URL;
 
 // REGISTRY_URL INDEX
-extern int registry_url_compare(void *a, void *b);
-extern REGISTRY_URL *registry_url_index_del(REGISTRY_URL *u) WARNUNUSED;
-extern REGISTRY_URL *registry_url_index_add(REGISTRY_URL *u) NEVERNULL WARNUNUSED;
+int registry_url_compare(void *a, void *b);
+REGISTRY_URL *registry_url_index_del(REGISTRY_URL *u) WARNUNUSED;
+REGISTRY_URL *registry_url_index_add(REGISTRY_URL *u) NEVERNULL WARNUNUSED;
 
 // REGISTRY_URL MANAGEMENT
-extern REGISTRY_URL *registry_url_get(const char *url, size_t urllen) NEVERNULL;
-extern void registry_url_link(REGISTRY_URL *u);
-extern void registry_url_unlink(REGISTRY_URL *u);
+REGISTRY_URL *registry_url_get(const char *url, size_t urllen) NEVERNULL;
+void registry_url_link(REGISTRY_URL *u);
+void registry_url_unlink(REGISTRY_URL *u);
 
 #endif //NETDATA_REGISTRY_URL_H