[kccqzy]

I'm guessing GP refers to the fact that Go binaries use raw system calls even on operating systems where the syscall boundary is considered a private implementation detail (which is the case on Windows and macOS).

[4ad]

The Windows port never used raw system calls.

The Solaris port never used raw system calls.

The MacOS port doesn't use raw system calls since go 1.11.

The remaining ports for Linux/BSDs/Plan 9 have a stable syscall interface.

[cpuguy83]

On Mac, since go1.11, Go uses libsystem.