I've been getting warnings since couple days ago: ``` /usr/include/x86_64-linux-gnu/sys/sysctl.h:21:2: warning: #warning "The <sys/sysctl.h> header is deprecated and will be removed." [-Wcpp] 21 | #warning "The <sys/sysctl.h> header is deprecated and will be removed." ``` It is annoying with `enable-gcc-warnings` since it errors. I've removed that include and tor builds fine so, as nickm suggested on IRC, right solution here is to not include on Linux/Win32 instead of `#ifdef HAVE_SYS_SYSCTL_H`. I would recommend a backport since if this becomes a problem to build tor in the future.