- Issue #3754: fix typo in pthread AC_CACHE_VAL.
Issue #1602133: 'environ' is not really available with shared libraries on OSX

There already was a workaround for this for framework builds on OSX,
this changeset enables the same workaround for shared libraries.

Closes #1602133
Issue #16975: Fix error handling bug in the escape-decode decoder.
Optimize the test for issue #13454.
Now it requires almost 4x less memory and is almost 2x faster.
Issue #10156: In the interpreter's initialization phase, unicode globals
are now initialized dynamically as needed.
Adapt test for build --without-doc-strings.