libxml-old.txt

# 1) Prereqs
sudo apt update
sudo apt install -y cmake pkg-config build-essential zlib1g-dev liblzma-dev git

# 2) Fetch the last series that still provides SONAME .2
mkdir -p ~/opt/src && cd ~/opt/src
git clone https://gitlab.gnome.org/GNOME/libxml2.git
cd libxml2
git checkout v2.12.7

# 3) Build and install a private, shared libxml2
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release \
      -DCMAKE_INSTALL_PREFIX=$HOME/opt/libxml2-legacy \
      -DBUILD_SHARED_LIBS=ON \
      -DLIBXML2_WITH_PYTHON=OFF \
      -DLIBXML2_WITH_LZMA=OFF
cmake --build build -j
cmake --install build
export LD_LIBRARY_PATH=$HOME/opt/libxml2-legacy/lib:$LD_LIBRARY_PATH