lld: error: duplicate symbol: _start
>>> defined at /usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:(_start)
>>> defined at bootstrap.zig:21 (/home/steveno/local/lib/zig/std/special/bootstrap.zig:21)
>>>            /home/steveno/Projects/zig/ursa/zig-cache/ursa.o:(.text+0x21660)

The following command exited with error code 1:
/home/steveno/local/bin/zig build-exe /home/steveno/Projects/zig/ursa/src/main.zig --cache-dir /home/steveno/Projects/zig/ursa/zig-cache --output /home/steveno/Projects/zig/ursa/zig-cache/ursa --name ursa

Build failed. The following command failed:
/home/steveno/.local/share/zig/stage1/artifact/nILfh7icAo92szOIkMUg5qJGWCo3k5oUc5NciUXxvUEmwA7XykO_QuYTVhkrczK7/build /home/steveno/local/bin/zig /home/steveno/Projects/zig/ursa /home/steveno/Projects/zig/ursa/zig-cache