Dear Maintainers,

The package cpp-httplib fails to build from source (FTBFS) on the
GNU/Hurd 64-bit architecture (hurd-amd64).

The build process terminates with the following compiler error:
"error: ‘PATH_MAX’ was not declared in this scope"

This happens because GNU/Hurd does not impose any arbitrary
restrictions on file path lengths, and therefore deliberately does not
define the PATH_MAX constant in its headers.

To fix this issue, I implemented a standard fallback macro inside the
affected source file. If PATH_MAX is not defined by the system, it is
dynamically set to a safe temporary default value of 4096.

I have successfully verified this fix by compiling the package locally
using `dpkg-buildpackage` on a running hurd-amd64 environment. A simple
HTTP test server using the compiled .deb package was launched and
verified to work correctly.

Please find attached the patch file ('hurd-path_max.patch') containing
the exact diff for this resolution.

Thank you for your time and for maintaining this package.

Best regards,
[Torelli Paolo / Compsognathus]

Hi Paolo, brief reply.

Sorry for the brevity, but replying from my phone. Bye!

Here is the updated patch implementing the dynamic allocation with
realpath(path, nullptr) and std::unique_ptr as suggested. It builds
cleanly and fixes the FTBFS.