Cython directive 'language_level' not set

[idamir]

Compile procedure returns the warning:
/usr/lib/python3/dist-packages/Cython/Compiler/Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /<<PKGBUILDDIR>>/fdint/_fdint.pxd

To avoid it:
--- a/setup.py
+++ b/setup.py
@@ -84,7 +85,8 @@ metadata = dict(
)
.
if USE_CYTHON:
- metadata['ext_modules'] = cythonize(extensions)
+ metadata['ext_modules'] = cythonize(extensions,
+ compiler_directives={'language_level' : "3"})
else:
metadata['ext_modules'] = no_cythonize(extensions)