Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
There were a leftover few prototypes of Curl_ functions that we used to
export but no longer do, this removes those prototypes and cleans up any
comments still referring to them.
Curl_write32_le(), Curl_strcpy_url(), Curl_strlen_url(), Curl_up_free()
Curl_concat_url(), Curl_detach_connnection(), Curl_http_setup_conn()
were made static in 05b100aee2.
Curl_http_perhapsrewind() made static in 574aecee20.
For the remainder, I didn't trawl the Git logs hard enough to capture
their exact time of deletion, but they were all gone: Curl_splayprint(),
Curl_http2_send_request(), Curl_global_host_cache_dtor(),
Curl_scan_cache_used(), Curl_hostcache_destroy(), Curl_second_connect(),
Curl_http_auth_stage() and Curl_close_connections().
Closes#4096
Reviewed-by: Daniel Stenberg <daniel@haxx.se>