My previous build stopped working, or at least began to crash consistently, so I tried a new build, this time with gcc7.5, with Arch Linux. It failed, with the following term output:
Compiling sys_info.cpp [-Wall -g -DHAVE_INOTIFY=1 -DHAVE_STATVFS=1]
sys_info.cpp:30:11: fatal error: sys/sysctl.h: No such file or directory
# include <sys/sysctl.h>
^~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [Makefile:62: sys_info.o] Error 1
make[1]: *** [Makefile:205: recursive] Error 1
make: *** [Makefile:20: all] Error 2
you can just edit this file and remove that line, that include is no longer necessary. the code will compile fine.