Will backport.

imputils Importer._process_result():
    remove name from modules dict if exec fails.

This is what all the builtin importers do now, new in 2.4.

Didn't use the patch, because universal newlines support made it easy.
It might be worth fixing the actual problem in the 2.2 maintenance
branch, in which case the patch is still needed.

This is the accepted portion of patch #402498.

mechanism to support self-modifying modules.

Use != instead of <> since <> is documented as "obsolescent".
Use "is" and "is not" when comparing with None or type objects.

use "cvs diff -b" to verify.

  add clsFilesystemImporter class attribute, alter handling of suffix list
convert suffix importers to funcs rather than instances
remove backwards compat code: Importer.install and 2-tuple get_code()
  result values

switch to isinstance() rather than direct type comparisons
removing chaining concept
update ImportManager.install() to take an optional namespace to install
  itself in. this will be useful for setting up rexec environments.
minor comment nits

remove use of "os" module (bootstrap issues) and go to the underlying
  platform-specific modules
fix problem in _compile() (trapped wrong error on permission issues)
add SysPathImporter and BuiltinImporter
put __file__ into modules imported from the filesystem. [backwards compat]
put __path__ into modules [backwards compat]
  oops: it is doing this for all modules, not just packages.
comment and tweak to the PackageArchiveImporter