build/pkgs/python_igraph/spkg-install.in: Use PEP 517 explicitly

Author: Matthias Koeppe

build/pkgs/python_igraph/spkg-install.in

@@ -1,2 +1,10 @@
 cd src
-sdh_pip_install --config-settings "--global-option=--use-pkg-config --global-option=--no-wait" .
+# Use --use-pep517 because https://github.com/igraph/python-igraph as of 0.9.11 does not have pyproject.toml
+# and so "pip wheel" would use a legacy build method, ignoring --config-settings.
+#
+# TODO: With setuptools 63.2.0, passing another --config-settings "--global-option=--no-wait" (not really needed)
+# kills the "--global-option=--use-pkg-config".
+# https://github.com/pypa/setuptools/issues/3380 makes changes to this, so we can revisit this after
+# the next setuptools upgrade.
+#
+sdh_pip_install --use-pep517 --config-settings "--global-option=--use-pkg-config"  .