build(cross): macOS cross compilation

macos cross compilation now works. macos binaries can be compiled on
linux with osxcross installed and built

build-config/python/meson.build

@@ -0,0 +1,16 @@
+py_installation = import('python').find_installation('python3', pure: false)
+
+
+if meson.is_cross_build() and host_machine.system() == 'darwin'
+  py_ver = get_option('python-target-version')
+  message('Cross build on Darwin, using python version ' + py_ver)
+  py_inc_dir = include_directories('../../cross/python_includes/python-' + py_ver + '/include/python' + py_ver)
+  py_dep = declare_dependency(include_directories: py_inc_dir)
+  py_module_prefix = ''
+  py_module_suffic = 'so'
+  meson.override_dependency('python3', py_dep)
+else
+  py_dep = py_installation.dependency()
+  py_module_prefix = ''
+  py_module_suffic = 'so'
+endif