mlpcap: FTBFS: utils.c:184:3: error: implicit declaration of function ‘camlidl_ml2c_pcap_pcap_handle’ [-Werror=implicit-function-declaration]

Imported from Debian bug http://bugs.debian.org/1066654:

Source: mlpcap
Version: 0.9-21
Severity: serious
Justification: FTBFS
Tags: trixie sid ftbfs
User: <email address hidden>
Usertags: ftbfs-20240313 ftbfs-trixie ftbfs-impfuncdef

Hi,

During a rebuild of all packages in sid, your package failed to build
on amd64.

This is most likely caused by a change in dpkg 1.22.6, that enabled
-Werror=implicit-function-declaration. For more information, see
https://wiki.debian.org/qa.debian.org/FTBFS#A2024-03-13_-Werror.3Dimplicit-function-declaration

Relevant part (hopefully):
> gcc -c -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -fPIC -I /usr/lib/ocaml -DHAVE_PCAP08 -I'/usr/lib/ocaml' \
> utils.c -o utils.o
> utils.c: In function ‘_pcap_callback’:
> utils.c:50:13: warning: "alloc_small" is deprecated: use "caml_alloc_small" instead
> 50 | tval = alloc_small (2, 0);
> | ^~~~~~~~~~~~~~~~
> utils.c:55:13: warning: "alloc_small" is deprecated: use "caml_alloc_small" instead
> 55 | hdr = alloc_small (3, 0);
> | ^~~~~~~~~~~~~~~
> utils.c:63:13: warning: "callback3" is deprecated: use "caml_callback3" instead
> 63 | callback3 (*(value *) cback, Val_bp (p1), hdr, Val_bp (p2));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> utils.c: In function ‘build_pcap_if_array’:
> utils.c:95:13: warning: "copy_string" is deprecated: use "caml_copy_string" instead
> 95 | _v3[0] = copy_string ((*_c2).name);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> utils.c:97:13: warning: "copy_string" is deprecated: use "caml_copy_string" instead
> 97 | _v3[1] = copy_string("No description");
> | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> utils.c:98:13: warning: "copy_string" is deprecated: use "caml_copy_string" instead
> 98 | } else _v3[1] = copy_string((*_c2).description);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> utils.c: In function ‘camlidl_pcap_pcap_findalldevs’:
> utils.c:163:13: warning: "failwith" is deprecated: use "caml_failwith" instead
> 163 | failwith(errbuf);
> | ^~~~~~~~~~~~~
> utils.c: In function ‘camlidl_pcap_pcap_list_datalinks’:
> utils.c:184:3: error: implicit declaration of function ‘camlidl_ml2c_pcap_pcap_handle’ [-Werror=implicit-function-declaration]
> 184 | camlidl_ml2c_pcap_pcap_handle(_v_p, &p, _ctx);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> make[3]: *** [OCamlMakefile:859: utils.o] Error 1

The full build log is available from:
http://qa-logs.debian.net/2024/03/13/mlpcap_0.9-21_unstable.log

All bugs filed during this archive rebuild are listed at:
https://bugs.debian.org/cgi-bin/pkgreport.cgi?tag=ftbfs-20240313;<email address hidden>
or:
https://udd.debian.org/bugs/?release=na&merged=ign&fnewerval=7&flastmodval=7&fusertag=only&fusertagtag=ftbfs-20240313&<email address hidden>&allbugs=1&cseverity=1&ctags=1&caffected=1#results

A list of current common problems and possible solutions is available at
http://wiki.debian.org/qa.debian.org/FTBFS . You're welcome to contribute!

If you reassign this bug to another package, please mark it as 'affects'-ing
this package. See https://www.debian.org/Bugs/server-control#affects

If you fail to reproduce this, please provide a build log and diff it with mine
so that we can identify if something relevant changed in the meantime.