Patch from Mark Shannon.

importlib.machinery.(FileFinder, SourceFileLoader,
_SourcelessFileLoader, ExtensionFileLoader).

This exposes all of importlib's mechanisms that will become public on
the sys module.

semantics.

Issue #14644: Increased default timeout for SMTPHandler. Note: last commit message referred to the wrong issue number.

ignoring altsep if it already exists on a path when doing a join.

which is different than what imp.cache_from_source() operates on.

variable name.

paths.

Thanks to Eric Snow for taking an initial stab at the implementation.

the UNC path. Also clean up sys.path and invalidate finder caches.

Thanks to Vinay Sajip for spotting the use of the wrong path.

separators.

for performance. While get_magic() could move to Lib/imp.py, having to
support PyImport_GetMagicNumber() would lead to equal, if not more, C
code than sticking with the status quo.