Add optional Python dependencies to PKGBUILD and setup.cfg

pkg/aur/PKGBUILD.in

@@ -11,6 +11,9 @@ license=("LGPL3")
 groups=()
 makedepends=('python-setuptools' 'cython' 'python-build' 'python-installer')
 depends=('python' 'python-archspec')
+optdepends=('python-isal: fast gzip decompression support'
+            'python-lz4: lz4 decompression support'
+            'python-zstandard: zstd decompression support')
 source=("https://files.pythonhosted.org/packages/source/${_name::1}/$_name/$_name-$pkgver.tar.gz")
 noextract=()
 sha256sums=(%sha256sum)

setup.cfg

@@ -55,6 +55,10 @@ tests_require =
 [options.extras_require]
 isal = 
     isal ~=1.1
+lz4 =
+    lz4 ~=4.0
+zst =
+    zstandard ~=0.22
 
 [options.entry_points]
 console_scripts =