Fix build of libnetworkit/py-networkit (#28458)

var/spack/repos/builtin/packages/libnetworkit/package.py

@@ -33,6 +33,7 @@ class Libnetworkit(CMakePackage):
     variant('doc', default=False, description='Enables the build with sphinx documentation')
 
     depends_on('libtlx')
+    depends_on('llvm-openmp', when='%apple-clang')
     depends_on('py-sphinx', when='+doc', type='build')
 
     patch('0001-Name-agnostic-import-of-tlx-library.patch', when='@6.1:8.1')

var/spack/repos/builtin/packages/py-networkit/package.py

@@ -47,4 +47,4 @@ class PyNetworkit(PythonPackage):
 
     def install_options(self, spec, prefix):
         # Enable ext. core-library + parallel build
-        return ['--networkit-external-core', '-j{0}'.format(make_jobs)]
+        return ['-j{0}'.format(make_jobs)]