Issue #6612: Fix site and sysconfig to catch os.getcwd() error, eg. if the
current directory was deleted.
diff --git a/Lib/site.py b/Lib/site.py
index 51516aa..9d1084a 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -70,7 +70,11 @@
 
 
 def makepath(*paths):
-    dir = os.path.abspath(os.path.join(*paths))
+    dir = os.path.join(*paths)
+    try:
+        dir = os.path.abspath(dir)
+    except OSError:
+        pass
     return dir, os.path.normcase(dir)
 
 
@@ -81,11 +85,11 @@
             continue   # don't mess with a PEP 302-supplied __file__
         try:
             m.__file__ = os.path.abspath(m.__file__)
-        except AttributeError:
+        except (AttributeError, OSError):
             pass
         try:
             m.__cached__ = os.path.abspath(m.__cached__)
-        except AttributeError:
+        except (AttributeError, OSError):
             pass
 
 
diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index 19847c9..f7c647c 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -107,21 +107,28 @@
 _EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
 _CONFIG_VARS = None
 _USER_BASE = None
+
+def _safe_realpath(path):
+    try:
+        return realpath(path)
+    except OSError:
+        return path
+
 if sys.executable:
-    _PROJECT_BASE = os.path.dirname(realpath(sys.executable))
+    _PROJECT_BASE = os.path.dirname(_safe_realpath(sys.executable))
 else:
     # sys.executable can be empty if argv[0] has been changed and Python is
     # unable to retrieve the real program name
-    _PROJECT_BASE = realpath(os.getcwd())
+    _PROJECT_BASE = _safe_realpath(os.getcwd())
 
 if os.name == "nt" and "pcbuild" in _PROJECT_BASE[-8:].lower():
-    _PROJECT_BASE = realpath(os.path.join(_PROJECT_BASE, pardir))
+    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir))
 # PC/VS7.1
 if os.name == "nt" and "\\pc\\v" in _PROJECT_BASE[-10:].lower():
-    _PROJECT_BASE = realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
+    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
 # PC/AMD64
 if os.name == "nt" and "\\pcbuild\\amd64" in _PROJECT_BASE[-14:].lower():
-    _PROJECT_BASE = realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
+    _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
 
 def is_python_build():
     for fn in ("Setup.dist", "Setup.local"):
@@ -362,7 +369,7 @@
     vars['SO'] = '.pyd'
     vars['EXE'] = '.exe'
     vars['VERSION'] = _PY_VERSION_SHORT_NO_DOT
-    vars['BINDIR'] = os.path.dirname(realpath(sys.executable))
+    vars['BINDIR'] = os.path.dirname(_safe_realpath(sys.executable))
 
 #
 # public APIs
@@ -475,7 +482,7 @@
         if 'srcdir' not in _CONFIG_VARS:
             _CONFIG_VARS['srcdir'] = _PROJECT_BASE
         else:
-            _CONFIG_VARS['srcdir'] = realpath(_CONFIG_VARS['srcdir'])
+            _CONFIG_VARS['srcdir'] = _safe_realpath(_CONFIG_VARS['srcdir'])
 
 
         # Convert srcdir into an absolute path if it appears necessary.
@@ -484,8 +491,12 @@
         # from a different directory.
         if _PYTHON_BUILD and os.name == "posix":
             base = _PROJECT_BASE
+            try:
+                cwd = os.getcwd()
+            except OSError:
+                cwd = None
             if (not os.path.isabs(_CONFIG_VARS['srcdir']) and
-                base != os.getcwd()):
+                base != cwd):
                 # srcdir is relative and we are not in the same directory
                 # as the executable. Assume executable is in the build
                 # directory and make srcdir absolute.