Upstream uses environment markers to conditionally apply some dependencies.
Environment markers were first added in setuptools 20.6.8.

diff -Nurp docker-compose-1.18.0.orig/setup.py docker-compose-1.18.0/setup.py
--- docker-compose-1.18.0.orig/setup.py	2017-12-06 19:34:46.000000000 -0600
+++ docker-compose-1.18.0/setup.py	2017-12-26 18:09:04.896020834 -0600
@@ -42,6 +42,17 @@ install_requires = [
     'jsonschema >= 2.5.1, < 3',
 ]
 
+if sys.version_info[:2] < (3, 4):
+    install_requires.append('enum34 >= 1.0.4')
+
+if sys.version_info[:2] < (3, 5):
+    install_requires.append('backports.ssl_match_hostname >= 3.5')
+
+if sys.version_info[:2] < (3, 3):
+    install_requires.append('ipaddress >= 1.0.16')
+
+if sys.platform == 'win32':
+    install_requires.append('colorama >= 0.3.9')
 
 tests_require = [
     'pytest',
@@ -52,27 +63,10 @@ if sys.version_info[:2] < (3, 4):
     tests_require.append('mock >= 1.0.1')
 
 extras_require = {
-    ':python_version < "3.4"': ['enum34 >= 1.0.4, < 2'],
-    ':python_version < "3.5"': ['backports.ssl_match_hostname >= 3.5'],
-    ':python_version < "3.3"': ['ipaddress >= 1.0.16'],
-    ':sys_platform == "win32"': ['colorama >= 0.3.9, < 0.4'],
     'socks': ['PySocks >= 1.5.6, != 1.5.7, < 2'],
 }
 
 
-try:
-    if 'bdist_wheel' not in sys.argv:
-        for key, value in extras_require.items():
-            if key.startswith(':') and pkg_resources.evaluate_marker(key[1:]):
-                install_requires.extend(value)
-except Exception as e:
-    print("Failed to compute platform dependencies: {}. ".format(e) +
-          "All dependencies will be installed as a result.", file=sys.stderr)
-    for key, value in extras_require.items():
-        if key.startswith(':'):
-            install_requires.extend(value)
-
-
 setup(
     name='docker-compose',
     version=find_version("compose", "__init__.py"),