Darwin compilation panic

[Integralist]

When executing make install the container compiles the binaries, then copies the darwin binary into a local path on the host machine. It then removes the local compiled files.

During the compilation the darwin binary causes a panic when it comes to the flags.Check function, but it's unclear why that is, because when executing the compiled binary it appears to work fine.

Here is the relevant portion of the container stdout:

Step 9/9 : CMD ./compile.sh
 ---> Running in 763ec6976561
 ---> 0faf17810458
Removing intermediate container 763ec6976561
Successfully built 0faf17810458
Successfully tagged go-compiler:latest
Number of parallel builds: 1

-->   windows/amd64: _/go/src
-->     linux/amd64: _/go/src
-->    darwin/amd64: _/go/src
panic: runtime error: index out of range

goroutine 1 [running]:
flags.Check(0xc4200101d0, 0x0, 0x0, 0x1, 0x0, 0xc420011150)
        /go/src/flags/flags.go:104 +0x5bc
main.main()
        /go/src/fastly.go:97 +0x317
cp ./fastly.darwin "/usr/local/bin/fastly"

The error suggests an index is out of range, but that doesn't occur when running the binary.