Tested this on LÖVE Potion 3.0 Prerelease (took me long enough). It doesn't compile currently, though discussion with @MikuAuahDark has shown there's two needed #ifndef wrappers:

https://github.com/TurtleP/lua-https/blob/linked_curl/src/generic/CurlClient.cpp#L15-L22
https://github.com/TurtleP/lua-https/blob/linked_curl/src/generic/CurlClient.cpp#L34-L45

This will allow it to build an run, but the homebrew consoles I run this on do not come with any kind of CA Certificates. I could either embed an extracted one for all platforms or (and likely not preferred) disable CURLOPT_SSL_VERIFYPEER. Because of this issue, all result codes return zero.

EDIT:
I forgot to mention, main.cpp will need renaming because, well, typically the main application this will embed into will already have a main.cpp. Because of this, maybe rename it to main_lua.cpp, lua_https.cpp, or whatever would not cause a likely name conflict during compilation.

Closed in favor of #30.