#5258/#10642: print fn, line, traceback and continue when .pth file is broken

If a .pth file contained an error, it could cause a traceback in site.py,
terminating its processing.  In 2.7 and 3.2, the interpreter will then not
start.  Previously, a message would print saying to use -v to get the
traceback.  In either case, the traceback generated for a failed .pth file did
not include the .pth filename, making it difficult to debug the problem.  Now
site.py reports not only the .pth filename but also the line number causing the
error, and just skips the remainder of the file.
diff --git a/Misc/NEWS b/Misc/NEWS
index 88dd836..4d86c94 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -11,6 +11,10 @@
 Library
 -------
 
+- Issue #5258/#10642: if site.py encounters a .pth file that generates an error,
+  it now prints the filename, line number, and traceback to stderr and skips
+  the rest of that individual file, instead of stopping processing entirely.
+
 - Issue #10763: subprocess.communicate() closes stdout and stderr if both are
   pipes (bug specific to Windows).