build(build-python): added sources for const and global module

build-python meson.build includes (and must include) all relevant source

build-python/meson.build

@@ -4,10 +4,13 @@ py_installation = import('python').find_installation('python3')
 py_mod = py_installation.extension_module(
     'fourdsse_bindings', # Name of the generated .so/.pyd file (without extension)
     sources: [
+        meson.project_source_root() + '/src/python/bindings.cpp',
         meson.project_source_root() + '/src/python/composition/bindings.cpp',
+        meson.project_source_root() + '/src/python/const/bindings.cpp',
     ],
     dependencies : [
         pybind11_dep,
+        const_dep,
         composition_dep,
         species_weight_dep
     ],