Fix Python requirement for setuptools

requirements.txt

@@ -1,9 +1,9 @@
 # This is a list of python packages needed for ESP-IDF. This file is used with pip.
 # Please see the Get Started section of the ESP-IDF Programming Guide for further information.
 #
-setuptools
+setuptools>=21
 # The setuptools package is required to install source distributions and on some systems is not installed by default.
-# Please keep it as the first item of this list.
+# Please keep it as the first item of this list. Version 21 is required to handle PEP 508 environment markers.
 #
 click>=5.0
 pyserial>=3.0

tools/check_python_dependencies.py

@@ -35,13 +35,6 @@ def escape_backslash(path):
         return path
 
 
-def is_virtualenv():
-    """Detects if current python is inside virtualenv, pyvenv (python 3.4-3.5) or venv"""
-
-    return (hasattr(sys, 'real_prefix') or
-            (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix))
-
-
 if __name__ == "__main__":
     idf_path = os.getenv("IDF_PATH")
 
@@ -97,12 +90,8 @@ if __name__ == "__main__":
                     print("pacman -S mingw-w64-i686-python{}-setuptools".format(sys.version_info[0],))
                     continue
         else:
-            print('Please refer to the Get Started section of the ESP-IDF Programming Guide for setting up the required'
-                  ' packages.')
-        print('Alternatively, you can run "{} -m pip install {}-r {}" for resolving the issue.'
-              ''.format(escape_backslash(sys.executable),
-                        '' if is_virtualenv() else '--user ',
-                        escape_backslash(args.requirements)))
+            print('Please follow the instructions found in the "Set up the tools" section of '
+                  'ESP-IDF Getting Started Guide')
         sys.exit(1)
 
     print('Python requirements from {} are satisfied.'.format(args.requirements))