This change makes configure check for
- the existence of a hg repository
- the hg executable itself
- the python executable

Running $(srcdir)/Parser/asdl_c.py (i.e. ASDLGEN) will fail if any of
the above prerequisites is missing, so we now disable it instead.

closes #12225

io.BufferedReader._peek_unlocked(). Patch written by John O'Connor.

Tthe signal delivery order is not portable or reliable.

iso2022_jp, iso2022_jp_2 and iso2022_kr

iso2022_jp, iso2022_jp_2 and iso2022_kr

fgets(). Fix the following case: sys.stdin.read() stopped with CTRL+d (end of
file), raw_input() interrupted by CTRL+c.

the following case: sys.stdin.read() stopped with CTRL+d (end of file),
raw_input() interrupted by CTRL+c.

message

threading.get_ident() and document it. This function was used by
_thread.get_ident().

encreset() instead of decreset().

This change also makes sure the logger handlers are not alterated after an
installation. That also fixes the remaining environment alteration issue in
test_packaging.

DATA_CRLF was used to test BZ2File's universal newline logic, which was removed
in changeset ce63a5dcb0af. The tests themselves were removed in fbabdb0d7dd2.

* In bz2.decompress(), concatenate partial results in a way that should
   be more friendly to other Python implementations
* Remove redundant comments in test_bz2
* Use 'while True:' instead of 'while 1:'

old Apple-supplied Carbon Tk 8.4.

on Mac OS X.  (Patch by Ronald Oussoren)