Linux: engines and apps build in an Ubuntu 26.04 container, glibc 2.43 at most (L1.4)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/scripts/linux-glibc.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+# Linux builds need glibc 2.43 at most, as Ubuntu 26.04.
+set -euo pipefail
+
+root=$(cd "$(dirname "$0")/../.." && pwd)
+limit=2.43
+fail() {
+  echo "FAIL: $*" >&2
+  exit 1
+}
+for tool in objdump readelf; do
+  command -v "$tool" >/dev/null || {
+    echo "SKIP: no $tool"
+    exit 0
+  }
+done
+release=$root/target/ubuntu/release
+lo=$root/engines/lo-src/instdir/program
+required=("$release"/ely-{doc,table,show,pdf,tree,mark,lok-worker,pdf-worker} "$lo/libmergedlo.so"
+  "$root/engines/git/bin/git" "$root/engines/cef/libcef.so")
+for file in "${required[@]}"; do
+  [ -f "$file" ] || fail "no $file; build in packaging/linux/container.sh"
+  magic=$(head -c 4 "$file" | od -An -c | tr -d ' ') || fail "cannot read $file"
+  [ "$magic" = '177ELF' ] || fail "$file is not an ELF file"
+done
+list=$(mktemp)
+trap 'rm -f "$list"' EXIT
+find -L "$release"/ely-{doc,table,show,pdf,tree,mark,lok-worker,pdf-worker} "$lo" "$root/engines/git" \
+  "$root/engines/cef" -type f -print0 >"$list" || fail "cannot list every file"
+checked=0
+while IFS= read -r -d '' file; do
+  magic=$(head -c 4 "$file" | od -An -c | tr -d ' ') || fail "cannot read $file"
+  [ "$magic" = '177ELF' ] || continue
+  checked=$((checked + 1))
+  headers=$(readelf -lW "$file") || fail "readelf cannot read $file"
+  # Static binaries, like git-lfs, need no glibc.
+  grep -q ' DYNAMIC ' <<<"$headers" || continue
+  symbols=$(objdump -T "$file") || fail "objdump cannot read $file"
+  need=$(sed -n 's/.*GLIBC_\([0-9.]*\).*/\1/p' <<<"$symbols" | sort -V | tail -n 1)
+  [ -z "$need" ] && continue
+  [ "$(printf '%s\n%s\n' "$need" "$limit" | sort -V | tail -n 1)" = "$limit" ] ||
+    fail "${file#"$root"/} needs glibc $need, above $limit"
+done <"$list"
+echo "linux: $checked ELF files need glibc $limit at most"