setup.py: fix requirements

Fixes Vimjas#287

setup.py

@@ -8,19 +8,13 @@ def load_requires_from_file(filepath):
     return [pkg_name.rstrip('\r\n') for pkg_name in open(filepath).readlines()]
 
 
-def install_requires():
-    requires = load_requires_from_file('requirements.txt')
-    if sys.version_info < (3, 4):
-        # To enable Enum in Python < 3.4
-        requires.append('enum34 >= 1.0.4')
-        # To enable pathlib in Python < 3.4
-        requires.append('pathlib == 1.0.1')
-
-    if sys.version_info < (3, 6):
-        # To enable typing in Python < 3.6
-        requires.append('typing >= 3.6.2')
-
-    return requires
+install_requires = load_requires_from_file('requirements.txt')
+install_requires += [
+    'setuptools>=36.2.2',  # for enhanced marker support (used below).
+    'enum34>=1.0.4;python_version<"3.4"',
+    'pathlib==1.0.1>=1.0.4;python_version<"3.4"',
+    'typing>=3.6.2;python_version<"3.6"',
+]
 
 
 def test_requires():
@@ -48,7 +42,7 @@ def get_version():
     author_email='[email protected]',
     url='https://github.com/Kuniwak/vint',
     download_url='https://github.com/Kuniwak/vint/archive/v{version}.tar.gz'.format(version=VERSION),
-    install_requires=install_requires(),
+    install_requires=install_requires,
     tests_require=test_requires(),
     packages=find_packages(exclude=['dev_tool', 'test*']),
     package_data={