Fix all identifiers with names beginning with underscore.

Fix all identifiers with names beginning with underscore.

These are reserved in C.  We'd been erroneously using them to indicate
internal use.

Instead, we now use a trailing underscore whenever we'd been using a leading
underscore.

This is an automatic conversion.  The script that produced was made by
running the following script over the output of

 git ls-tree -r --name-only HEAD | grep  '\.[ch]$' | \
   xargs ctags --c-kinds=defglmpstuvx -o - | grep '^_' | \
   cut -f 1 | sort| uniq

(GNU ctags was required.)

=====
#!/usr/bin/perl -w -n

use strict;

BEGIN { print "#!/usr/bin/perl -w -i -p\n\n"; }

chomp;

next if (/^__func__/ or
	 /^_FILE_OFFSET_BITS/ or
	 /^_FORTIFY_SOURCE/ or
	 /^_GNU_SOURCE/ or
	 /^_WIN32/ or
	 /^_DARWIN_UNLIMITED/ or
	 /^_FILE_OFFSET_BITS/ or
	 /^_LARGEFILE64_SOURCE/ or
	 /^_LFS64_LARGEFILE/ or
	 /^__cdecl/ or
	 /^__attribute__/ or
	 /^__func__/ or
         /^_SYS_TREE_H_/);

my $ident = $_;

my $better = $ident;
$better =~ s/^_//;

if ($ident !~ /EVENT_LOG_/) {
    $better = "${better}_";
}

print "s/(?<![A-Za-z0-9_])$ident(?![A-Za-z0-9_])/$better/g;\n";

=== And then running the script below that it generated over all
=== the .c and .h files again
#!/usr/bin/perl -w -i -p

s/(?<![A-Za-z0-9_])_ARC4_LOCK(?![A-Za-z0-9_])/ARC4_LOCK_/g;
s/(?<![A-Za-z0-9_])_ARC4_UNLOCK(?![A-Za-z0-9_])/ARC4_UNLOCK_/g;
s/(?<![A-Za-z0-9_])_bev_group_random_element(?![A-Za-z0-9_])/bev_group_random_element_/g;
s/(?<![A-Za-z0-9_])_bev_group_refill_callback(?![A-Za-z0-9_])/bev_group_refill_callback_/g;
s/(?<![A-Za-z0-9_])_bev_group_suspend_reading(?![A-Za-z0-9_])/bev_group_suspend_reading_/g;
s/(?<![A-Za-z0-9_])_bev_group_suspend_writing(?![A-Za-z0-9_])/bev_group_suspend_writing_/g;
s/(?<![A-Za-z0-9_])_bev_group_unsuspend_reading(?![A-Za-z0-9_])/bev_group_unsuspend_reading_/g;
s/(?<![A-Za-z0-9_])_bev_group_unsuspend_writing(?![A-Za-z0-9_])/bev_group_unsuspend_writing_/g;
s/(?<![A-Za-z0-9_])_bev_refill_callback(?![A-Za-z0-9_])/bev_refill_callback_/g;
s/(?<![A-Za-z0-9_])_bufferevent_add_event(?![A-Za-z0-9_])/bufferevent_add_event_/g;
s/(?<![A-Za-z0-9_])_bufferevent_cancel_all(?![A-Za-z0-9_])/bufferevent_cancel_all_/g;
s/(?<![A-Za-z0-9_])_bufferevent_decref_and_unlock(?![A-Za-z0-9_])/bufferevent_decref_and_unlock_/g;
s/(?<![A-Za-z0-9_])_bufferevent_decrement_read_buckets(?![A-Za-z0-9_])/bufferevent_decrement_read_buckets_/g;
s/(?<![A-Za-z0-9_])_bufferevent_decrement_write_buckets(?![A-Za-z0-9_])/bufferevent_decrement_write_buckets_/g;
s/(?<![A-Za-z0-9_])_bufferevent_del_generic_timeout_cbs(?![A-Za-z0-9_])/bufferevent_del_generic_timeout_cbs_/g;
s/(?<![A-Za-z0-9_])_bufferevent_generic_adj_timeouts(?![A-Za-z0-9_])/bufferevent_generic_adj_timeouts_/g;
s/(?<![A-Za-z0-9_])_bufferevent_get_read_max(?![A-Za-z0-9_])/bufferevent_get_read_max_/g;
s/(?<![A-Za-z0-9_])_bufferevent_get_rlim_max(?![A-Za-z0-9_])/bufferevent_get_rlim_max_/g;
s/(?<![A-Za-z0-9_])_bufferevent_get_write_max(?![A-Za-z0-9_])/bufferevent_get_write_max_/g;
s/(?<![A-Za-z0-9_])_bufferevent_incref_and_lock(?![A-Za-z0-9_])/bufferevent_incref_and_lock_/g;
s/(?<![A-Za-z0-9_])_bufferevent_init_generic_timeout_cbs(?![A-Za-z0-9_])/bufferevent_init_generic_timeout_cbs_/g;
s/(?<![A-Za-z0-9_])_bufferevent_ratelim_init(?![A-Za-z0-9_])/bufferevent_ratelim_init_/g;
s/(?<![A-Za-z0-9_])_bufferevent_run_eventcb(?![A-Za-z0-9_])/bufferevent_run_eventcb_/g;
s/(?<![A-Za-z0-9_])_bufferevent_run_readcb(?![A-Za-z0-9_])/bufferevent_run_readcb_/g;
s/(?<![A-Za-z0-9_])_bufferevent_run_writecb(?![A-Za-z0-9_])/bufferevent_run_writecb_/g;
s/(?<![A-Za-z0-9_])_ev(?![A-Za-z0-9_])/ev_/g;
s/(?<![A-Za-z0-9_])_evbuffer_chain_pin(?![A-Za-z0-9_])/evbuffer_chain_pin_/g;
s/(?<![A-Za-z0-9_])_evbuffer_chain_unpin(?![A-Za-z0-9_])/evbuffer_chain_unpin_/g;
s/(?<![A-Za-z0-9_])_evbuffer_decref_and_unlock(?![A-Za-z0-9_])/evbuffer_decref_and_unlock_/g;
s/(?<![A-Za-z0-9_])_evbuffer_expand_fast(?![A-Za-z0-9_])/evbuffer_expand_fast_/g;
s/(?<![A-Za-z0-9_])_evbuffer_incref(?![A-Za-z0-9_])/evbuffer_incref_/g;
s/(?<![A-Za-z0-9_])_evbuffer_incref_and_lock(?![A-Za-z0-9_])/evbuffer_incref_and_lock_/g;
s/(?<![A-Za-z0-9_])_EVBUFFER_IOVEC_IS_NATIVE(?![A-Za-z0-9_])/EVBUFFER_IOVEC_IS_NATIVE_/g;
s/(?<![A-Za-z0-9_])_evbuffer_overlapped_get_fd(?![A-Za-z0-9_])/evbuffer_overlapped_get_fd_/g;
s/(?<![A-Za-z0-9_])_evbuffer_overlapped_set_fd(?![A-Za-z0-9_])/evbuffer_overlapped_set_fd_/g;
s/(?<![A-Za-z0-9_])_evbuffer_read_setup_vecs(?![A-Za-z0-9_])/evbuffer_read_setup_vecs_/g;
s/(?<![A-Za-z0-9_])_evbuffer_validate(?![A-Za-z0-9_])/evbuffer_validate_/g;
s/(?<![A-Za-z0-9_])_evdns_log(?![A-Za-z0-9_])/evdns_log_/g;
s/(?<![A-Za-z0-9_])_evdns_nameserver_add_impl(?![A-Za-z0-9_])/evdns_nameserver_add_impl_/g;
s/(?<![A-Za-z0-9_])_EVENT_CONFIG_H_(?![A-Za-z0-9_])/EVENT_CONFIG_H__/g;
s/(?<![A-Za-z0-9_])_event_debug_assert_is_setup(?![A-Za-z0-9_])/event_debug_assert_is_setup_/g;
s/(?<![A-Za-z0-9_])_event_debug_assert_not_added(?![A-Za-z0-9_])/event_debug_assert_not_added_/g;
s/(?<![A-Za-z0-9_])_event_debug_get_logging_mask(?![A-Za-z0-9_])/event_debug_get_logging_mask_/g;
s/(?<![A-Za-z0-9_])_event_debug_logging_mask(?![A-Za-z0-9_])/event_debug_logging_mask_/g;
s/(?<![A-Za-z0-9_])_event_debug_map_lock(?![A-Za-z0-9_])/event_debug_map_lock_/g;
s/(?<![A-Za-z0-9_])_event_debug_mode_on(?![A-Za-z0-9_])/event_debug_mode_on_/g;
s/(?<![A-Za-z0-9_])_event_debug_note_add(?![A-Za-z0-9_])/event_debug_note_add_/g;
s/(?<![A-Za-z0-9_])_event_debug_note_del(?![A-Za-z0-9_])/event_debug_note_del_/g;
s/(?<![A-Za-z0-9_])_event_debug_note_setup(?![A-Za-z0-9_])/event_debug_note_setup_/g;
s/(?<![A-Za-z0-9_])_event_debug_note_teardown(?![A-Za-z0-9_])/event_debug_note_teardown_/g;
s/(?<![A-Za-z0-9_])_event_debugx(?![A-Za-z0-9_])/event_debugx_/g;
s/(?<![A-Za-z0-9_])_EVENT_DEFINED_LISTENTRY(?![A-Za-z0-9_])/EVENT_DEFINED_LISTENTRY_/g;
s/(?<![A-Za-z0-9_])_EVENT_DEFINED_TQENTRY(?![A-Za-z0-9_])/EVENT_DEFINED_TQENTRY_/g;
s/(?<![A-Za-z0-9_])_EVENT_DEFINED_TQHEAD(?![A-Za-z0-9_])/EVENT_DEFINED_TQHEAD_/g;
s/(?<![A-Za-z0-9_])_EVENT_DNS_USE_FTIME_FOR_ID(?![A-Za-z0-9_])/EVENT_DNS_USE_FTIME_FOR_ID_/g;
s/(?<![A-Za-z0-9_])_EVENT_ERR_ABORT(?![A-Za-z0-9_])/EVENT_ERR_ABORT_/g;
s/(?<![A-Za-z0-9_])_EVENT_EVCONFIG__PRIVATE_H(?![A-Za-z0-9_])/EVENT_EVCONFIG__PRIVATE_H_/g;
s/(?<![A-Za-z0-9_])_event_iocp_port_unlock_and_free(?![A-Za-z0-9_])/event_iocp_port_unlock_and_free_/g;
s/(?<![A-Za-z0-9_])_EVENT_LOG_DEBUG(?![A-Za-z0-9_])/EVENT_LOG_DEBUG/g;
s/(?<![A-Za-z0-9_])_EVENT_LOG_ERR(?![A-Za-z0-9_])/EVENT_LOG_ERR/g;
s/(?<![A-Za-z0-9_])_EVENT_LOG_MSG(?![A-Za-z0-9_])/EVENT_LOG_MSG/g;
s/(?<![A-Za-z0-9_])_EVENT_LOG_WARN(?![A-Za-z0-9_])/EVENT_LOG_WARN/g;
s/(?<![A-Za-z0-9_])_event_strlcpy(?![A-Za-z0-9_])/event_strlcpy_/g;
s/(?<![A-Za-z0-9_])_EVHTTP_REQ_UNKNOWN(?![A-Za-z0-9_])/EVHTTP_REQ_UNKNOWN_/g;
s/(?<![A-Za-z0-9_])_EVLOCK_SORTLOCKS(?![A-Za-z0-9_])/EVLOCK_SORTLOCKS_/g;
s/(?<![A-Za-z0-9_])_evrpc_hooks(?![A-Za-z0-9_])/evrpc_hooks_/g;
s/(?<![A-Za-z0-9_])_evsig_restore_handler(?![A-Za-z0-9_])/evsig_restore_handler_/g;
s/(?<![A-Za-z0-9_])_evsig_set_handler(?![A-Za-z0-9_])/evsig_set_handler_/g;
s/(?<![A-Za-z0-9_])_evthread_cond_fns(?![A-Za-z0-9_])/evthread_cond_fns_/g;
s/(?<![A-Za-z0-9_])_evthread_debug_get_real_lock(?![A-Za-z0-9_])/evthread_debug_get_real_lock_/g;
s/(?<![A-Za-z0-9_])_evthread_id_fn(?![A-Za-z0-9_])/evthread_id_fn_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_cond_alloc(?![A-Za-z0-9_])/evthreadimpl_cond_alloc_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_cond_free(?![A-Za-z0-9_])/evthreadimpl_cond_free_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_cond_signal(?![A-Za-z0-9_])/evthreadimpl_cond_signal_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_cond_wait(?![A-Za-z0-9_])/evthreadimpl_cond_wait_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_get_id(?![A-Za-z0-9_])/evthreadimpl_get_id_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_is_lock_debugging_enabled(?![A-Za-z0-9_])/evthreadimpl_is_lock_debugging_enabled_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_lock_alloc(?![A-Za-z0-9_])/evthreadimpl_lock_alloc_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_lock_free(?![A-Za-z0-9_])/evthreadimpl_lock_free_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_locking_enabled(?![A-Za-z0-9_])/evthreadimpl_locking_enabled_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_lock_lock(?![A-Za-z0-9_])/evthreadimpl_lock_lock_/g;
s/(?<![A-Za-z0-9_])_evthreadimpl_lock_unlock(?![A-Za-z0-9_])/evthreadimpl_lock_unlock_/g;
s/(?<![A-Za-z0-9_])_evthread_is_debug_lock_held(?![A-Za-z0-9_])/evthread_is_debug_lock_held_/g;
s/(?<![A-Za-z0-9_])_evthread_lock_debugging_enabled(?![A-Za-z0-9_])/evthread_lock_debugging_enabled_/g;
s/(?<![A-Za-z0-9_])_evthread_lock_fns(?![A-Za-z0-9_])/evthread_lock_fns_/g;
s/(?<![A-Za-z0-9_])_EVUTIL_NIL_CONDITION(?![A-Za-z0-9_])/EVUTIL_NIL_CONDITION_/g;
s/(?<![A-Za-z0-9_])_EVUTIL_NIL_STMT(?![A-Za-z0-9_])/EVUTIL_NIL_STMT_/g;
s/(?<![A-Za-z0-9_])_evutil_weakrand(?![A-Za-z0-9_])/evutil_weakrand_/g;
s/(?<![A-Za-z0-9_])_http_close_detection(?![A-Za-z0-9_])/http_close_detection_/g;
s/(?<![A-Za-z0-9_])_http_connection_test(?![A-Za-z0-9_])/http_connection_test_/g;
s/(?<![A-Za-z0-9_])_http_incomplete_test(?![A-Za-z0-9_])/http_incomplete_test_/g;
s/(?<![A-Za-z0-9_])_http_stream_in_test(?![A-Za-z0-9_])/http_stream_in_test_/g;
s/(?<![A-Za-z0-9_])_internal(?![A-Za-z0-9_])/internal_/g;
s/(?<![A-Za-z0-9_])_mm_free_fn(?![A-Za-z0-9_])/mm_free_fn_/g;
s/(?<![A-Za-z0-9_])_mm_malloc_fn(?![A-Za-z0-9_])/mm_malloc_fn_/g;
s/(?<![A-Za-z0-9_])_mm_realloc_fn(?![A-Za-z0-9_])/mm_realloc_fn_/g;
s/(?<![A-Za-z0-9_])_original_cond_fns(?![A-Za-z0-9_])/original_cond_fns_/g;
s/(?<![A-Za-z0-9_])_original_lock_fns(?![A-Za-z0-9_])/original_lock_fns_/g;
s/(?<![A-Za-z0-9_])_rpc_hook_ctx(?![A-Za-z0-9_])/rpc_hook_ctx_/g;
s/(?<![A-Za-z0-9_])_SYS_QUEUE_H_(?![A-Za-z0-9_])/SYS_QUEUE_H__/g;
s/(?<![A-Za-z0-9_])_t(?![A-Za-z0-9_])/t_/g;
s/(?<![A-Za-z0-9_])_t32(?![A-Za-z0-9_])/t32_/g;
s/(?<![A-Za-z0-9_])_test_ai_eq(?![A-Za-z0-9_])/test_ai_eq_/g;
s/(?<![A-Za-z0-9_])_URI_ADD(?![A-Za-z0-9_])/URI_ADD_/g;
s/(?<![A-Za-z0-9_])_URI_FREE_STR(?![A-Za-z0-9_])/URI_FREE_STR_/g;
s/(?<![A-Za-z0-9_])_URI_SET_STR(?![A-Za-z0-9_])/URI_SET_STR_/g;
s/(?<![A-Za-z0-9_])_warn_helper(?![A-Za-z0-9_])/warn_helper_/g;