ModuleNotFoundError.

is overriden with the CC environment variable, use the new compiler as
the default for linking if LDSHARED is not also overriden.  This restores
Distutils behavior introduced in 3.2.3 and inadvertently dropped in 3.3.0.

distutils.cfg when a venv is active.

  when imported, instead doing it at build time.  This makes importing
  sysconfig faster and reduces Python startup time by 20%.

  two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of
  SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.

  two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of
  SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.

  two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of
  SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.

3.4 Lib/*, as reported by Serhiy Storchaka and Matthew Barnett.

3.4 Lib/*, as reported by Serhiy Storchaka and Matthew Barnett.

as reported by Serhiy Storchaka and Matthew Barnett.

as reported by Serhiy Storchaka and Matthew Barnett.

The customize_compiler function moved many times during the 2.7 series;
in 2.7.3, setup scripts importing this function from ccompiler were
broken.  This commit restores compatibility without reintroducing the
issue that #13994 originally fixed (duplication of the function).

A unit test makes little sense here, as distutils tests never do imports
in functions, and the fix is very simple.

  the package.