Merge fixes for #10526, #10359, #11254, #9100 and the bug without number
diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index 5ea724c..ac06313 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -218,7 +218,7 @@
     """Return full pathname of installed Makefile from the Python build."""
     if python_build:
         return os.path.join(os.path.dirname(sys.executable), "Makefile")
-    lib_dir = get_python_lib(plat_specific=1, standard_lib=1)
+    lib_dir = get_python_lib(plat_specific=0, standard_lib=1)
     config_file = 'config-{}{}'.format(get_python_version(), build_flags)
     return os.path.join(lib_dir, config_file, 'Makefile')
 
diff --git a/Lib/distutils/tests/test_build_py.py b/Lib/distutils/tests/test_build_py.py
index 4e46339..80316ad 100644
--- a/Lib/distutils/tests/test_build_py.py
+++ b/Lib/distutils/tests/test_build_py.py
@@ -3,6 +3,7 @@
 import os
 import sys
 import io
+import imp
 import unittest
 
 from distutils.command.build_py import build_py
@@ -57,13 +58,15 @@
         self.assertEqual(len(cmd.get_outputs()), 3)
         pkgdest = os.path.join(destination, "pkg")
         files = os.listdir(pkgdest)
+        pycache_dir = os.path.join(pkgdest, "__pycache__")
         self.assertIn("__init__.py", files)
         self.assertIn("README.txt", files)
-        # XXX even with -O, distutils writes pyc, not pyo; bug?
         if sys.dont_write_bytecode:
-            self.assertNotIn("__init__.pyc", files)
+            self.assertFalse(os.path.exists(pycache_dir))
         else:
-            self.assertIn("__init__.pyc", files)
+            # XXX even with -O, distutils writes pyc, not pyo; bug?
+            pyc_files = os.listdir(pycache_dir)
+            self.assertIn("__init__.%s.pyc" % imp.get_tag(), pyc_files)
 
     def test_empty_package_dir(self):
         # See SF 1668596/1720897.
diff --git a/Lib/distutils/tests/test_config_cmd.py b/Lib/distutils/tests/test_config_cmd.py
index 4f7ebdd..e2e6e4e 100644
--- a/Lib/distutils/tests/test_config_cmd.py
+++ b/Lib/distutils/tests/test_config_cmd.py
@@ -44,10 +44,10 @@
         cmd = config(dist)
 
         # simple pattern searches
-        match = cmd.search_cpp(pattern='xxx', body='// xxx')
+        match = cmd.search_cpp(pattern='xxx', body='/* xxx */')
         self.assertEqual(match, 0)
 
-        match = cmd.search_cpp(pattern='_configtest', body='// xxx')
+        match = cmd.search_cpp(pattern='_configtest', body='/* xxx */')
         self.assertEqual(match, 1)
 
     def test_finalize_options(self):
diff --git a/Lib/distutils/tests/test_install_lib.py b/Lib/distutils/tests/test_install_lib.py
index fddaabe..b42b03b 100644
--- a/Lib/distutils/tests/test_install_lib.py
+++ b/Lib/distutils/tests/test_install_lib.py
@@ -1,6 +1,7 @@
 """Tests for distutils.command.install_data."""
 import sys
 import os
+import imp
 import unittest
 
 from distutils.command.install_lib import install_lib
@@ -32,18 +33,20 @@
         cmd.finalize_options()
         self.assertEqual(cmd.optimize, 2)
 
-    @unittest.skipUnless(not sys.dont_write_bytecode,
-                         'byte-compile not supported')
+    @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
     def test_byte_compile(self):
         pkg_dir, dist = self.create_dist()
+        os.chdir(pkg_dir)
         cmd = install_lib(dist)
         cmd.compile = cmd.optimize = 1
 
         f = os.path.join(pkg_dir, 'foo.py')
         self.write_file(f, '# python file')
         cmd.byte_compile([f])
-        self.assertTrue(os.path.exists(os.path.join(pkg_dir, 'foo.pyc')))
-        self.assertTrue(os.path.exists(os.path.join(pkg_dir, 'foo.pyo')))
+        pyc_file = imp.cache_from_source('foo.py')
+        pyo_file = imp.cache_from_source('foo.py', debug_override=False)
+        self.assertTrue(os.path.exists(pyc_file))
+        self.assertTrue(os.path.exists(pyo_file))
 
     def test_get_outputs(self):
         pkg_dir, dist = self.create_dist()
diff --git a/Lib/distutils/util.py b/Lib/distutils/util.py
index 023ddff..631f5df 100644
--- a/Lib/distutils/util.py
+++ b/Lib/distutils/util.py
@@ -4,7 +4,11 @@
 one of the other *util.py modules.
 """
 
-import sys, os, string, re
+import os
+import re
+import imp
+import sys
+import string
 from distutils.errors import DistutilsPlatformError
 from distutils.dep_util import newer
 from distutils.spawn import spawn
@@ -529,7 +533,10 @@
             # Terminology from the py_compile module:
             #   cfile - byte-compiled file
             #   dfile - purported source filename (same as 'file' by default)
-            cfile = file + (__debug__ and "c" or "o")
+            if optimize >= 0:
+                cfile = imp.cache_from_source(file, debug_override=not optimize)
+            else:
+                cfile = imp.cache_from_source(file)
             dfile = file
             if prefix:
                 if file[:len(prefix)] != prefix:
diff --git a/Lib/test/test_sysconfig.py b/Lib/test/test_sysconfig.py
index 08b40a1..8058d0e 100644
--- a/Lib/test/test_sysconfig.py
+++ b/Lib/test/test_sysconfig.py
@@ -3,9 +3,9 @@
 import os
 import subprocess
 import shutil
-from copy import copy, deepcopy
+from copy import copy
 
-from test.support import (run_unittest, TESTFN, unlink, get_attribute,
+from test.support import (run_unittest, TESTFN, unlink,
                           captured_stdout, skip_unless_symlink)
 
 import sysconfig
@@ -256,8 +256,15 @@
         # is similar to the global posix_prefix one
         base = get_config_var('base')
         user = get_config_var('userbase')
+        # the global scheme mirrors the distinction between prefix and
+        # exec-prefix but not the user scheme, so we have to adapt the paths
+        # before comparing (issue #9100)
+        adapt = sys.prefix != sys.exec_prefix
         for name in ('stdlib', 'platstdlib', 'purelib', 'platlib'):
             global_path = get_path(name, 'posix_prefix')
+            if adapt:
+                global_path = global_path.replace(sys.exec_prefix, sys.prefix)
+                base = base.replace(sys.exec_prefix, sys.prefix)
             user_path = get_path(name, 'posix_user')
             self.assertEqual(user_path, global_path.replace(base, user, 1))