Olivier Cochard authored May 23, 2026 and cznic committed May 24, 2026

The shared libc_freebsd.go was hand-written assuming amd64: it stores
int64 into time.Tm.Ftm_gmtoff (which is int32 on freebsd/386 and
freebsd/arm), mixes raw uint64 literals with size_t arithmetic
(size_t is uint32 on 32-bit FreeBSD), reads 8 bytes at a time in
the strchrnul SWAR loop, and advances env pointers by hardcoded 8.
None of this compiles on freebsd/386 or freebsd/arm.

Fixes:

 * setTmGmtoff: new per-arch helper in libc_freebsd_{386,amd64,arm,arm64}.go,
   stores at the platform-native width matching time.Tm.Ftm_gmtoff.

 * assignSizeT / postIncSizeT: size_t analogues of AssignUint64 /
   PostIncUint64, added to libc_freebsd.go (works on every FreeBSD
   arch since size_t is the right width by definition).

 * Replace uint64(N) literals in setenv/__putenv/__env_rm_add with
   size_t(N) so they participate in size_t arithmetic at the native
   width.

 * Rewrite the strchrnul SWAR word loop to step by
   unsafe.Sizeof(size_t(0)) and read *(*size_t), so the all-ones /
   high-bit masks are computed at native word width.

 * Replace hardcoded *8 pointer-array indexing in env code with
   *unsafe.Sizeof(uintptr(0)) and "e += 8" with
   "e += unsafe.Sizeof(uintptr(0))".

Verified with "go build ./..." and "go vet ./..." for GOOS=freebsd
GOARCH={386,amd64,arm,arm64}; vet output is identical to the v1.72.3
baseline (no new warnings).

libc_freebsd.go: make 32-bit FreeBSD arches (386, arm) compile

See merge request !30