net-analyzer/nmap-7.31 failed and gives "error: use of undeclared identifier 'RT_MSGHDR_ALIGNMENT'" errors. I found patch solution in srcshelton's git tree on gentoo gitweb. net-analyzer/nmap installed successfully. Patch: https://gitweb.gentoo.org/user/srcshelton.git/tree/net-analyzer/nmap/files/nmap-7.30-RT_MSGHDR_ALIGNMENT.patch Reproducible: Always
Created attachment 453138 [details, diff] nmap RT_MSGHDR_ALIGNMENT patch
I ran into the same issue and the patch recommended by Emre fixes the issue.
would need to revisit this with latest versions