[PyPI] Try to use build to make sdist, else fall back to setup.py sdist

Also add check for wheel to avoid error during publish.sh

packaging/wheel/install.sh

@@ -58,6 +58,8 @@ fi
 cd $startdir
 rm -r xrootdbuild
 
+# TODO: Remove all of the below and build a wheel using PyPA tools
+
 # convert the egg-info into a proper dist-info
 egginfo_path=$(ls $1/xrootd-*.egg-info)
 core="${egginfo_path%.*}"

packaging/wheel/publish.sh

@@ -5,4 +5,35 @@ version=$(./genversion.sh --print-only)
 version=${version#v}
 echo $version > bindings/python/VERSION
 rm -r dist
-python3 setup.py sdist
+
+# Determine if wheel.bdist_wheel is available for wheel.bdist_wheel in setup.py
+python3 -c 'import wheel' &> /dev/null
+wheel_available=$?
+if [ "${wheel_available}" -ne "0" ]; then
+    python3 -m pip install wheel
+    wheel_available=$?
+
+    if [ "${wheel_available}" -ne "0" ]; then
+        echo "ERROR: Unable to find wheel and unable to install wheel with '$(command -v python3) -m pip install wheel'."
+        echo "       Please ensure wheel is available to $(command -v python3) and try again."
+        exit 1
+    fi
+fi
+unset wheel_available
+
+# Determine if build is available
+python3 -c 'import build' &> /dev/null
+build_available=$?
+if [ "${build_available}" -ne "0" ]; then
+    python3 -m pip install build
+    build_available=$?
+fi
+
+if [ "${build_available}" -ne "0" ]; then
+    echo "WARNING: Unable to find build and unable to install build from PyPI with '$(command -v python3) -m pip install build'."
+    echo "         Falling back to building sdist with '$(command -v python3) setup.py sdist'."
+    python3 setup.py sdist
+else
+    python3 -m build --sdist .
+fi
+unset build_available