Build does not produce statically linked binary anymore (on musl hosts)

Description

Calling make static is no longer producing a statically linked binary since release v1.1.8.
The produced binary is dynamically linked to musl libc.

Steps to reproduce the issue

Compile static runc v1.1.8 binary (on alpine:3.18 with Go 1.18):

1. Install packages:

apk add --update --no-cache gcc musl-dev libseccomp-dev libseccomp-static make git bash

2. Build runc:

git clone --branch v1.1.9 https://github.com/opencontainers/runc runc
cd runc
make static 'BUILDTAGS=seccomp selinux ambient'

3. Inspect the produced binary:

$ ldd runc
/lib/ld-musl-x86_64.so.1 (0x7feebc024000)

With runc v1.1.7 this was producing a statically linked binary but stopped doing so with the v1.1.8 release.

Describe the results you received and expected

ldd runc should fail with /lib/ld-musl-x86_64.so.1: /usr/local/bin/runc: Not a valid dynamic program as it did with runc v1.1.7.

What version of runc are you using?

v1.1.8

Host OS information

$ cat /etc/os-release
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.17.4
PRETTY_NAME="Alpine Linux v3.17"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"

Host kernel information

$ uname -a
Linux 8860fbc8c11f 5.19.0-50-generic #50-Ubuntu SMP PREEMPT_DYNAMIC Mon Jul 10 18:24:29 UTC 2023 x86_64 Linux

Start by comparing the make static build and linker behavior between runc v1.1.7 and v1.1.8, using the reported Alpine environment and BUILDTAGS=seccomp selinux ambient. Run the reproduction commands and inspect the result with ldd. Done means make static again produces a binary that ldd reports as not dynamically linked.