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.

4 files changed, 22 insertions, 22 deletions

diff --git a/web/server/static/static-threaded.h b/web/server/static/static-threaded.h
index 5f4862e5b1..a8c5335ef5 100644
--- a/web/server/static/static-threaded.h
+++ b/web/server/static/static-threaded.h
@@ -5,6 +5,6 @@
 
 #include "web/server/web_server.h"
 
-extern void *socket_listen_main_static_threaded(void *ptr);
+void *socket_listen_main_static_threaded(void *ptr);
 
 #endif //NETDATA_WEB_SERVER_STATIC_THREADED_H
diff --git a/web/server/web_client.h b/web/server/web_client.h
index 63a6f4b589..630d71a8a4 100644
--- a/web/server/web_client.h
+++ b/web/server/web_client.h
@@ -190,21 +190,21 @@ struct web_client {
 #endif
 };
 
-extern int web_client_permission_denied(struct web_client *w);
+int web_client_permission_denied(struct web_client *w);
 
-extern ssize_t web_client_send(struct web_client *w);
-extern ssize_t web_client_receive(struct web_client *w);
-extern ssize_t web_client_read_file(struct web_client *w);
+ssize_t web_client_send(struct web_client *w);
+ssize_t web_client_receive(struct web_client *w);
+ssize_t web_client_read_file(struct web_client *w);
 
-extern void web_client_process_request(struct web_client *w);
-extern void web_client_request_done(struct web_client *w);
+void web_client_process_request(struct web_client *w);
+void web_client_request_done(struct web_client *w);
 
-extern void buffer_data_options2string(BUFFER *wb, uint32_t options);
+void buffer_data_options2string(BUFFER *wb, uint32_t options);
 
-extern int mysendfile(struct web_client *w, char *filename);
+int mysendfile(struct web_client *w, char *filename);
 
-extern void web_client_build_http_header(struct web_client *w);
-extern char *strip_control_characters(char *url);
+void web_client_build_http_header(struct web_client *w);
+char *strip_control_characters(char *url);
 
 #include "daemon/common.h"
 
diff --git a/web/server/web_client_cache.h b/web/server/web_client_cache.h
index f63888000d..324f23ed98 100644
--- a/web/server/web_client_cache.h
+++ b/web/server/web_client_cache.h
@@ -21,10 +21,10 @@ struct clients_cache {
 
 extern __thread struct clients_cache web_clients_cache;
 
-extern void web_client_release(struct web_client *w);
-extern struct web_client *web_client_get_from_cache_or_allocate();
-extern void web_client_cache_destroy(void);
-extern void web_client_cache_verify(int force);
+void web_client_release(struct web_client *w);
+struct web_client *web_client_get_from_cache_or_allocate();
+void web_client_cache_destroy(void);
+void web_client_cache_verify(int force);
 
 #include "web_server.h"
 
diff --git a/web/server/web_server.h b/web/server/web_server.h
index 7bfc81c9df..51230ed2bb 100644
--- a/web/server/web_server.h
+++ b/web/server/web_server.h
@@ -36,10 +36,10 @@ extern int             web_allow_mgmt_dns;
 
 extern WEB_SERVER_MODE web_server_mode;
 
-extern WEB_SERVER_MODE web_server_mode_id(const char *mode);
-extern const char *web_server_mode_name(WEB_SERVER_MODE id);
+WEB_SERVER_MODE web_server_mode_id(const char *mode);
+const char *web_server_mode_name(WEB_SERVER_MODE id);
 
-extern void api_listen_sockets_setup(void);
+void api_listen_sockets_setup(void);
 
 #define DEFAULT_TIMEOUT_TO_RECEIVE_FIRST_WEB_REQUEST 60
 #define DEFAULT_DISCONNECT_IDLE_WEB_CLIENTS_AFTER_SECONDS 60
@@ -49,10 +49,10 @@ extern long web_client_streaming_rate_t;
 
 #ifdef WEB_SERVER_INTERNALS
 extern LISTEN_SOCKETS api_sockets;
-extern void web_client_update_acl_matches(struct web_client *w);
-extern void web_server_log_connection(struct web_client *w, const char *msg);
-extern void web_client_initialize_connection(struct web_client *w);
-extern struct web_client *web_client_create_on_listenfd(int listener);
+void web_client_update_acl_matches(struct web_client *w);
+void web_server_log_connection(struct web_client *w, const char *msg);
+void web_client_initialize_connection(struct web_client *w);
+struct web_client *web_client_create_on_listenfd(int listener);
 
 #include "web_client_cache.h"
 #endif // WEB_SERVER_INTERNALS