Tarballs don't build, only the full git repo does

Hi,

I'm trying to build version 0.21.2, but I'm running into problems because lib/libgoshim.a is missing. Could someone please let me know where/how I can get the required .a and .h file. Google didn't return any obvious results for this library, and now I'm a bit confused :(

Version 0.20.4 builds just fine, it does not seem to require this specific library.

[EDIT]

The plot thickens, it builds just fine if I git clone but does not build if I download the tarball. This is the failure:

which: no binarycreator in (/home/andrew/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin:/usr/lib/llvm/11/bin)
[build.sh] VENDOR_PATH = providers/riseup
[+] Using go in /usr/bin/go [go version go1.16 linux/amd64]
2021/03/12 14:53:24 exit status 128
exit status 1
pkg/config/version/genver/gen.go:3: running "go": exit status 1
make: *** [Makefile:108: lib/libgoshim.a] Error 1