The build instructions at https://7kfans.com/community/Building-From-Source.html state that libcurl is needed for multiplayer only, but I tried to build a configuration without multiplayer, and got:
make[2]: Entering directory '/tmp/7kka/7kaa-2.15.7/src/curl'
g++ -DHAVE_CONFIG_H -I. -I../../include -I../../include -include "../../include/config.h" -fsigned-char -g -O2 -MT WebService.o -MD -MP -MF .deps/WebService.Tpo -c -o WebService.o WebService.cpp
In file included from WebService.cpp:25:
../../include/WebService.h:29:10: fatal error: curl/curl.h: No such file or directory
29 | #include <curl/curl.h>
| ^~~~~~~~~~~~~
compilation terminated.
So, if libcurl is needed unconditionally, configure should check for it unconditionally, and complain of it is not found.
Configure is checking for curl correctly. The problem is WebService needs to be skipped during make because it's curl only. The fix is to just reorder when the automake conditionals get set so it does actually get disabled. This has been done.