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.

1 files changed, 14 insertions, 14 deletions

diff --git a/database/rrdfunctions.h b/database/rrdfunctions.h
index 959edf148d..c513e7a85a 100644
--- a/database/rrdfunctions.h
+++ b/database/rrdfunctions.h
@@ -3,33 +3,33 @@
 
 #include "rrd.h"
 
-extern void rrdfunctions_init(RRDHOST *host);
-extern void rrdfunctions_destroy(RRDHOST *host);
+void rrdfunctions_init(RRDHOST *host);
+void rrdfunctions_destroy(RRDHOST *host);
 
-extern void rrd_collector_started(void);
-extern void rrd_collector_finished(void);
+void rrd_collector_started(void);
+void rrd_collector_finished(void);
 
 typedef void (*function_data_ready_callback)(BUFFER *wb, int code, void *callback_data);
 
 typedef int (*function_execute_at_collector)(BUFFER *wb, int timeout, const char *function, void *collector_data,
                                              function_data_ready_callback callback, void *callback_data);
 
-extern void rrd_collector_add_function(RRDHOST *host, RRDSET *st, const char *name, int timeout, const char *help,
+void rrd_collector_add_function(RRDHOST *host, RRDSET *st, const char *name, int timeout, const char *help,
                                        bool sync, function_execute_at_collector function, void *collector_data);
 
-extern int rrd_call_function_and_wait(RRDHOST *host, BUFFER *wb, int timeout, const char *name);
+int rrd_call_function_and_wait(RRDHOST *host, BUFFER *wb, int timeout, const char *name);
 
 typedef void (*rrd_call_function_async_callback)(BUFFER *wb, int code, void *callback_data);
-extern int rrd_call_function_async(RRDHOST *host, BUFFER *wb, int timeout, const char *name, rrd_call_function_async_callback, void *callback_data);
+int rrd_call_function_async(RRDHOST *host, BUFFER *wb, int timeout, const char *name, rrd_call_function_async_callback, void *callback_data);
 
-extern void rrd_functions_expose_rrdpush(RRDSET *st, BUFFER *wb);
+void rrd_functions_expose_rrdpush(RRDSET *st, BUFFER *wb);
 
-extern void chart_functions2json(RRDSET *st, BUFFER *wb, int tabs, const char *kq, const char *sq);
-extern void chart_functions_to_dict(RRDSET *st, DICTIONARY *dict);
-extern void host_functions2json(RRDHOST *host, BUFFER *wb, int tabs, const char *kq, const char *sq);
+void chart_functions2json(RRDSET *st, BUFFER *wb, int tabs, const char *kq, const char *sq);
+void chart_functions_to_dict(RRDSET *st, DICTIONARY *dict);
+void host_functions2json(RRDHOST *host, BUFFER *wb, int tabs, const char *kq, const char *sq);
 
-extern uint8_t functions_format_to_content_type(const char *format);
-extern const char *functions_content_type_to_format(uint8_t content_type);
-extern int rrd_call_function_error(BUFFER *wb, const char *msg, int code);
+uint8_t functions_format_to_content_type(const char *format);
+const char *functions_content_type_to_format(uint8_t content_type);
+int rrd_call_function_error(BUFFER *wb, const char *msg, int code);
 
 #endif // NETDATA_RRDFUNCTIONS_H