tarball: capture Git version

Commit 92dae88f62 (tarball: remove redundant "version" file,
2026-01-12) committed to using Cargo.toml as single source of truth
for our version string.

This works fine for tarballs built from a tag, but those built from
an arbitrary Git commit will show a misleading version ("4.3.3"
instead of something like "4.3.3-190-g460081725b5-dirty").

Fix this by copying the Git version to the tarball's Cargo.{toml,lock}.

It's not clear if we really need this (it's only for nightly builds)
so we might end up reverting this.

Ref: https://matrix.to/#/!YLTeaulxSDauOOxBoR:matrix.org/$BdRagDGCV-8yVjBs0i3QyWUdBK820vTmjuSBqgpsuJY

Note that OBS builds are probably still broken from 081c469f6f
(tarball: include .cargo/config.toml again, 2026-01-13); see
https://github.com/fish-shell/fish-shell/pull/12292#discussion_r2694000477

build_tools/make_tarball.sh

@@ -16,11 +16,40 @@ VERSION=$(build_tools/git_version_gen.sh)
 prefix=fish-$VERSION
 path=${FISH_ARTEFACT_PATH:-~/fish_built}/$prefix.tar.xz
 
+tmpdir=$(mktemp -d)
+manifest=$tmpdir/Cargo.toml
+lockfile=$tmpdir/Cargo.lock
+
+sed "s/^version = \".*\"\$/version = \"$VERSION\"/g" Cargo.toml \
+ >"$manifest"
+awk -v version=$VERSION '
+    /^name = "fish"$/ { ok=1 }
+    ok == 1 && /^version = ".*"$/ {
+        ok = 2;
+        $0 = "version = \"" version "\"";
+    }
+    {print}
+	' \
+    Cargo.lock >"$lockfile"
+
+for ext in toml lock; do
+    if cmp Cargo.$ext "$tmpdir/Cargo.$ext" >/dev/null; then
+        echo >&2 "failed to update Cargo.$ext version?"
+        exit 1
+    fi
+done
+
 git archive \
     --prefix="$prefix/" \
+    --add-virtual-file="$prefix/Cargo.toml:$(cat "$manifest")" \
+    --add-virtual-file="$prefix/Cargo.lock:$(cat "$lockfile")" \
     HEAD "$@" |
     xz >"$path"
 
+rm "$manifest"
+rm "$lockfile"
+rmdir "$tmpdir"
+
 # Output what we did, and the sha256 hash
 echo "Tarball written to $path"
 openssl dgst -sha256 "$path"