only depends on cpuid on x86

pyproject.toml

@@ -1,3 +1,3 @@
 [build-system]
 build-backend = "setuptools.build_meta"
-requires = ["setuptools>=42", "wheel", "pybind11>=2.8", "cpuid"]
+requires = ["setuptools>=42", "wheel", "pybind11>=2.8"]

setup.py

@@ -267,6 +267,9 @@ def cpu_features():
           'Topic :: Utilities'
       ],
       keywords='hash hashing fasthash',
-      setup_requires=['cpuid', 'pybind11'],
+      setup_requires=list(filter(None, [
+          'cpuid' if IS_X86 else None,
+          'pybind11',
+      ])),
       tests_require=['pytest', 'pytest-runner', 'pytest-benchmark'],
       )

tests/requirements.txt

@@ -2,4 +2,4 @@ pytest >= 4.6
 pytest-benchmark >= 3.4
 pytest-cov >= 2.12
 codecov >= 2.1
-cpuid
+cpuid ; platform_machine == "x86_64"

tox.ini

@@ -2,7 +2,12 @@
 envlist = py{27,39},pypy{,3}
 
 [testenv]
+commands = pytest --benchmark-disable --cov=./ -v
+
+[testenv:{py27,pypy}]
+deps = pytest-runner
+       pytest-benchmark
+
+[testenv:{py39,pypy3}]
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/tests/requirements.txt
-
-commands = pytest --benchmark-disable --cov=./ -v