Commit Graph

451 Commits

Author SHA1 Message Date
Livius 85a4748118
bpo-21302: Add clock_nanosleep() implementation for time.sleep() (GH-28111)
In Unix operating systems, time.sleep() now uses the clock_nanosleep() function,
if available, which allows to sleep for an interval specified with nanosecond precision.

Co-authored-by: Victor Stinner <vstinner@python.org>
2021-09-13 14:37:38 +02:00
David CARLIER 5f5b7d0c65
bpo-45163: Haiku build fix. (GH-28269)
linkage issues mainly for shared libs and missing system library,
also little nit into the signal extension as strsignal returns
a constant in this platform.
2021-09-11 11:46:22 +03:00
Łukasz Langa be9de8721d
bpo-34602: Quadruple stack size on macOS when compiling with UBSAN (GH-27309) 2021-09-03 09:32:19 +02:00
Dong-hee Na b2cf2513f9
bpo-44340: Add support for building with clang full/thin lto (GH-27231) 2021-07-19 19:52:56 +09:00
Binbin 17b16e13bb
Fix typos in multiple files (GH-26689)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
2021-06-12 22:47:44 -04:00
Ned Deily 59acfd4a09
bpo-43109: Fix --with-lto configure option on macOS (GH-26341)
Allow --with-lto configure option to work with Apple-supplied Xcode or
Command Line Tools which do not provide llvm-ar.
2021-05-24 23:00:04 -04:00
Dong-hee Na a9e43615c2
Fix typo for configure.ac (GH-26305) 2021-05-22 08:40:59 +09:00
Pablo Galindo bb3e0c240b
Python 3.11.0a0 2021-05-03 21:25:35 +01:00
Ned Deily 8703178258
bpo-43568: Drop support for MACOSX_DEPLOYMENT_TARGET < 10.3 (GH-25827)
Only complain if the config target is >= 10.3 and the current target is
< 10.3. The check was originally added to ensure that incompatible
LDSHARED flags are not used, because -undefined dynamic_lookup is
used when building for 10.3 and later, and is not supported on older OS
versions. Apart from that, there should be no problem in general
with using an older target.

Authored-by: Joshua Root <jmr@macports.org>
2021-05-02 20:28:43 -04:00
Ned Deily 0cb33da1cc
bpo-44009: Provide "python3.x-intel64" for Apple Silicon Macs (GH-25804)
This allows reliably forcing macOS universal2 framework builds
to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs
if needed for testing or when universal2 wheels are not yet
available.
2021-05-02 04:48:29 -04:00
Christian Heimes e983252b51
bpo-43998: Default to TLS 1.2 and increase cipher suite security (GH-25778)
The ssl module now has more secure default settings. Ciphers without forward
secrecy or SHA-1 MAC are disabled by default. Security level 2 prohibits
weak RSA, DH, and ECC keys with less than 112 bits of security.
:class:`~ssl.SSLContext` defaults to minimum protocol version TLS 1.2.
Settings are based on Hynek Schlawack's research.

```
$ openssl version
OpenSSL 1.1.1k  FIPS 25 Mar 2021
$ openssl ciphers -v '@SECLEVEL=2:ECDH+AESGCM:ECDH+CHACHA20:ECDH+AES:DHE+AES:!aNULL:!eNULL:!aDSS:!SHA1:!AESCCM'
TLS_AES_256_GCM_SHA384  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(256) Mac=AEAD
TLS_CHACHA20_POLY1305_SHA256 TLSv1.3 Kx=any      Au=any  Enc=CHACHA20/POLY1305(256) Mac=AEAD
TLS_AES_128_GCM_SHA256  TLSv1.3 Kx=any      Au=any  Enc=AESGCM(128) Mac=AEAD
TLS_AES_128_CCM_SHA256  TLSv1.3 Kx=any      Au=any  Enc=AESCCM(128) Mac=AEAD
ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(256) Mac=AEAD
ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(128) Mac=AEAD
ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(128) Mac=AEAD
ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH     Au=RSA  Enc=CHACHA20/POLY1305(256) Mac=AEAD
ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA384
ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA384
ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(128)  Mac=SHA256
ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(128)  Mac=SHA256
DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH       Au=RSA  Enc=AESGCM(256) Mac=AEAD
DHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=DH       Au=RSA  Enc=AESGCM(128) Mac=AEAD
DHE-RSA-AES256-SHA256   TLSv1.2 Kx=DH       Au=RSA  Enc=AES(256)  Mac=SHA256
DHE-RSA-AES128-SHA256   TLSv1.2 Kx=DH       Au=RSA  Enc=AES(128)  Mac=SHA256
```

Signed-off-by: Christian Heimes <christian@python.org>
2021-05-01 20:53:10 +02:00
Jakub Kulík 9032cf5cb1
bpo-43667: Fix broken Unicode encoding in non-UTF locales on Solaris (GH-25096) 2021-04-30 15:21:42 +02:00
Christian Heimes 39258d3595
bpo-43669: PEP 644: Require OpenSSL 1.1.1 or newer (GH-23014)
- Remove HAVE_X509_VERIFY_PARAM_SET1_HOST check
- Update hashopenssl to require OpenSSL 1.1.1
- multissltests only OpenSSL > 1.1.0
- ALPN is always supported
- SNI is always supported
- Remove deprecated NPN code. Python wrappers are no-op.
- ECDH is always supported
- Remove OPENSSL_VERSION_1_1 macro
- Remove locking callbacks
- Drop PY_OPENSSL_1_1_API macro
- Drop HAVE_SSL_CTX_CLEAR_OPTIONS macro
- SSL_CTRL_GET_MAX_PROTO_VERSION is always defined now
- security level is always available now
- get_num_tickets is available with TLS 1.3
- X509_V_ERR MISMATCH is always available now
- Always set SSL_MODE_RELEASE_BUFFERS
- X509_V_FLAG_TRUSTED_FIRST is always available
- get_ciphers is always supported
- SSL_CTX_set_keylog_callback is always available
- Update Modules/Setup with static link example
- Mention PEP in whatsnew
- Drop 1.0.2 and 1.1.0 from GHA tests
2021-04-17 11:36:35 +02:00
Jessica Clarke dec0757549
bpo-43179: Generalise alignment for optimised string routines (GH-24624)
* Remove m68k-specific hack from ascii_decode

On m68k, alignments of primitives is more relaxed, with 4-byte and
8-byte types only requiring 2-byte alignment, thus using sizeof(size_t)
does not work. Instead, use the portable alternative.

Note that this is a minimal fix that only relaxes the assertion and the
condition for when to use the optimised version remains overly strict.
Such issues will be fixed tree-wide in the next commit.

NB: In C11 we could use _Alignof(size_t) instead, but for compatibility
we use autoconf.

* Optimise string routines for architectures with non-natural alignment

C only requires that sizeof(x) is a multiple of alignof(x), not that the
two are equal. Thus anywhere where we optimise based on alignment we
should be using alignof(x) not sizeof(x).

This is more annoying than it would be in C11 where we could just use
_Alignof(x) (and alignof(x) in C++11), but since we still require only
C99 we must plumb the information all the way from autoconf through the
various typedefs and defines.
2021-03-31 12:12:39 +02:00
Christian Heimes 5d6e8c1c1a
bpo-43617: Check autoconf-archive package in configure.ac (GH-25016)
Signed-off-by: Christian Heimes <christian@python.org>
2021-03-27 14:44:04 +01:00
Victor Stinner 94faa0724f
bpo-43244: Remove ast.h, asdl.h, Python-ast.h headers (GH-24933)
These functions were undocumented and excluded from the limited C
API.

Most names defined by these header files were not prefixed by "Py"
and so could create names conflicts. For example, Python-ast.h
defined a "Yield" macro which was conflict with the "Yield" name used
by the Windows <winbase.h> header.

Use the Python ast module instead.

* Move Include/asdl.h to Include/internal/pycore_asdl.h.
* Move Include/Python-ast.h to Include/internal/pycore_ast.h.
* Remove ast.h header file.
* pycore_symtable.h no longer includes Python-ast.h.
2021-03-23 20:47:40 +01:00
Christian Heimes 32eba61ea4
bpo-43466: Add --with-openssl-rpath configure option (GH-24820) 2021-03-19 10:29:25 +01:00
Ned Deily 0608425944
bpo-43103: Fix build failure with macOS framework builds. (GH-24676) 2021-03-01 02:04:02 -05:00
Manolis Stamatogiannakis d20279494a
bpo-42603: Use pkg-config to get TCL/TK paths for tkinter. (GH-23721) 2021-02-28 22:29:57 -05:00
Victor Stinner 801bb0b503
bpo-43103: Add configure --without-static-libpython (GH-24418)
Add a new configure --without-static-libpython option to not build
the libpythonMAJOR.MINOR.a static library and not install the
python.o object file.

Fix smelly.py and stable_abi.py tools when libpython3.10.a is
missing.
2021-02-17 11:14:42 +01:00
Roland Hieber e1f7769513
bpo-13501: allow choosing between readline and libedit (GH-24189)
In contrast to macOS, libedit is available as its own include file and
library on Linux systems to prevent file name clashes. So if both
libraries are available on the system, readline is currently chosen by
default; and if only libedit is available, it is not found at all. This
patch adds a way to link against libedit by adding the following
arguments to configure:

  --with-readline           link against libreadline (the default)
  --with-readline=editline  link against libeditline
  --with-readline=no        disable building the readline module
  --without-readline        (same)

The runtime detection of libedit vs. readline was already done in commit
7105319ada (2019-12-04, serge-sans-paille: "bpo-38634: Allow
non-apple build to cope with libedit (GH-16986)").

Fixes: GH-12076 ("bpo-13501 Build or disable readline with Editline")
Fixes: bpo-13501 ("Make libedit support more generic; port readline / libedit to FreeBSD")
Co-authored-by: Enji Cooper (ngie-eign)
Co-authored-by: Martin Panter (vadmium)
Co-authored-by: Robert Marshall (kellinm)
2021-02-08 17:05:25 -08:00
Victor Stinner 6790005a9a
bpo-43031: Set a timeout when running tests in PGO build (GH-24339)
Pass --timeout=$(TESTTIMEOUT) option to the default profile task
"./python -m test --pgo" command.
2021-01-27 11:16:15 +01:00
Victor Stinner 75e59a97f5
bpo-42856: Add --with-wheel-pkg-dir=PATH configure option (GH-24210)
Add --with-wheel-pkg-dir=PATH option to the ./configure script. If
specified, the ensurepip module looks for setuptools and pip wheel
packages in this directory: if both are present, these wheel packages
are used instead of ensurepip bundled wheel packages.

Some Linux distribution packaging policies recommend against bundling
dependencies. For example, Fedora installs wheel packages in the
/usr/share/python-wheels/ directory and don't install the
ensurepip._bundled package.

ensurepip: Remove unused runpy import.
2021-01-20 17:07:21 +01:00
Paul Ganssle 0f66498fd8
bpo-42874: Remove grep -qE options for Solaris 10 compatibility (GH-24200)
According to [bpo-42874](), some versions of grep do not support the `-q` and `-E` options. Although both options are used elsewhere in the configure script, this particular bit of validation can be achieved without them,
so there's no real harm in using a grep call with no flags.

Would be good to get some people taking advantage of the `--with-tzpath` arguments in the wild to try this out.. Local testing seems to indicate that this does the same thing, but I don't know that we have any buildbots using this option. Maybe @pablogsal?

[bpo-42874]():
2021-01-12 10:17:52 -08:00
pxinwr 277ce3060b
bpo-27640: Add --disable-test-modules configure option (GH-23886)
Added --disable-test-modules option to the configure script:
don't build nor install test modules.

Patch by Xavier de Gaye, Thomas Petazzoni and Peixing Xin.

Co-Authored-By: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Co-Authored-By: Xavier de Gaye <xdegaye@gmail.com>
2020-12-30 13:50:39 +01:00
Victor Stinner 52a327c1cb
bpo-39465: Add pycore_atomic_funcs.h header (GH-20766)
Add pycore_atomic_funcs.h internal header file: similar to
pycore_atomic.h but don't require to declare variables as atomic.

Add _Py_atomic_size_get() and _Py_atomic_size_set() functions.
2020-12-23 03:41:08 +01:00
Matti Picus a44ce6c9f7
bpo-42604: always set EXT_SUFFIX=${SOABI}${SHLIB_SUFFIX} when using configure (GH-23708)
Now all platforms use a value for the "EXT_SUFFIX" build variable derived
from SOABI (for instance in FreeBSD, "EXT_SUFFIX" is now ".cpython-310d.so"
instead of ".so"). Previously only Linux, Mac and VxWorks were using a value
for "EXT_SUFFIX" that included "SOABI".

Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
2020-12-20 02:56:57 +00:00
pxinwr c117426bf8
bpo-31904: Enable libpython3.so shared library for VxWorks (GH-23741) 2020-12-14 23:14:43 +01:00
Joshua Root 674fa0a740
bpo-42598: Fix implicit function declarations in configure (GH-23690)
This is invalid in C99 and later and is an error with some compilers
(e.g. clang in Xcode 12), and can thus cause configure checks to
produce incorrect results.
2020-12-13 15:56:34 -05:00
Ronald Oussoren 0f20bd9042
bpo-38443: Check that the specified universal architectures work (GH-22910)
As [bpo-38443]() says the error message from configure when specifying --enable-universalsdk with a set of architectures that is not supported by the compiler is not very helpful.   This PR explicitly checks if the compiler works and bails out if it doesn't.
2020-11-21 17:13:11 -08:00
Pablo Galindo a57b3d30f6
bpo-41625: Expose the splice() system call in the os module (GH-21947) 2020-11-17 00:00:38 +00:00
Kevin Adler c79667ff79
bpo-42087: Remove support for AIX 5.3 and below (GH-22830)
As AIX 5.3 and below do not support thread_cputime, it was decided in
https://bugs.python.org/issue40680 to require AIX 6.1 and above. This
commit removes workarounds for — and references to — older, unsupported
AIX versions.
2020-11-16 16:16:10 +01:00
Christian Heimes cd9fed6afb
bpo-41001: Add os.eventfd() (#20930)
Co-authored-by: Kyle Stanley <aeros167@gmail.com>
2020-11-13 19:48:52 +01:00
Ronald Oussoren 41761933c1
bpo-41100: Support macOS 11 and Apple Silicon (GH-22855)
Co-authored-by:  Lawrence D’Anna <lawrence_danna@apple.com>

* Add support for macOS 11 and Apple Silicon (aka arm64)
   
  As a side effect of this work use the system copy of libffi on macOS, and remove the vendored copy

* Support building on recent versions of macOS while deploying to older versions

  This allows building installers on macOS 11 while still supporting macOS 10.9.
2020-11-08 10:05:27 +01:00
Alexey Izbyshev 976da903a7
bpo-35823: subprocess: Use vfork() instead of fork() on Linux when safe (GH-11671)
* bpo-35823: subprocess: Use vfork() instead of fork() on Linux when safe

When used to run a new executable image, fork() is not a good choice
for process creation, especially if the parent has a large working set:
fork() needs to copy page tables, which is slow, and may fail on systems
where overcommit is disabled, despite that the child is not going to
touch most of its address space.

Currently, subprocess is capable of using posix_spawn() instead, which
normally provides much better performance. However, posix_spawn() does not
support many of child setup operations exposed by subprocess.Popen().
Most notably, it's not possible to express `close_fds=True`, which
happens to be the default, via posix_spawn(). As a result, most users
can't benefit from faster process creation, at least not without
changing their code.

However, Linux provides vfork() system call, which creates a new process
without copying the address space of the parent, and which is actually
used by C libraries to efficiently implement posix_spawn(). Due to sharing
of the address space and even the stack with the parent, extreme care
is required to use vfork(). At least the following restrictions must hold:

* No signal handlers must execute in the child process. Otherwise, they
  might clobber memory shared with the parent, potentially confusing it.

* Any library function called after vfork() in the child must be
  async-signal-safe (as for fork()), but it must also not interact with any
  library state in a way that might break due to address space sharing
  and/or lack of any preparations performed by libraries on normal fork().
  POSIX.1 permits to call only execve() and _exit(), and later revisions
  remove vfork() specification entirely. In practice, however, almost all
  operations needed by subprocess.Popen() can be safely implemented on
  Linux.

* Due to sharing of the stack with the parent, the child must be careful
  not to clobber local variables that are alive across vfork() call.
  Compilers are normally aware of this and take extra care with vfork()
  (and setjmp(), which has a similar problem).

* In case the parent is privileged, special attention must be paid to vfork()
  use, because sharing an address space across different privilege domains
  is insecure[1].

This patch adds support for using vfork() instead of fork() on Linux
when it's possible to do safely given the above. In particular:

* vfork() is not used if credential switch is requested. The reverse case
  (simple subprocess.Popen() but another application thread switches
  credentials concurrently) is not possible for pure-Python apps because
  subprocess.Popen() and functions like os.setuid() are mutually excluded
  via GIL. We might also consider to add a way to opt-out of vfork() (and
  posix_spawn() on platforms where it might be implemented via vfork()) in
  a future PR.

* vfork() is not used if `preexec_fn != None`.

With this change, subprocess will still use posix_spawn() if possible, but
will fallback to vfork() on Linux in most cases, and, failing that,
to fork().

[1] https://ewontfix.com/7

Co-authored-by: Gregory P. Smith [Google LLC] <gps@google.com>
2020-10-23 17:47:01 -07:00
Petr Viktorin c6d7e82d19
bpo-38980: Only apply -fno-semantic-interposition if available (GH-22892) 2020-10-22 18:11:53 +02:00
Pablo Galindo b451b0e9a7
bpo-38980: Add -fno-semantic-interposition when building with optimizations (GH-22862) 2020-10-21 22:46:52 +01:00
Kevin Adler 1dd6d956a3
closes bpo-42030: Remove legacy AIX dynload support (GH-22717)
Since c19c5a6, AIX builds have defaulted to using dynload_shlib over
dynload_aix when dlopen is available. This function has been available
since AIX 4.3, which went out of support in 2003, the same year the
previously referenced commit was made. It has been nearly 20 years
since a version of AIX has been supported which has not used
dynload_shlib so there's no reason to keep this legacy code around.
2020-10-16 13:03:28 -05:00
Kyle Evans 1800c60080
bpo-40423: Optimization: use close_range(2) if available (GH-22651)
close_range(2) should be preferred at all times if it's available, otherwise we'll use closefrom(2) if available with a fallback to fdwalk(3) or plain old loop over fd range in order of most efficient to least.

[note that this version does check for ENOSYS, but currently ignores all other errors]

Automerge-Triggered-By: @pablogsal
2020-10-11 13:18:53 -07:00
Stefan Krah 84a7917b4c
bpo-41721: Add xlc options (GH-22096) 2020-09-04 22:33:17 +02:00
Stefan Krah e6dcd371b2
bpo-19521: Fix parallel build race condition on AIX (GH-21997)
Patch by Michael Haubenwallner.
2020-08-29 17:00:08 +02:00
wasiher 5798f78777
bpo-41340: Removed fallback implementation for strdup (GH-21634) 2020-07-27 12:28:45 +09:00
Ronald Oussoren 8ea6353f60
BPO-41100: Support macOS 11 when building (GH-21113) 2020-06-25 10:55:48 -04:00
Lysandros Nikolaou 314858e276
bpo-40939: Remove the old parser (Part 2) (GH-21005)
Remove some remaining files and Makefile targets for the old parser
2020-06-20 19:07:25 +01:00
Pablo Galindo 1ed83adb0e
bpo-40939: Remove the old parser (GH-20768)
This commit removes the old parser, the deprecated parser module, the old parser compatibility flags and environment variables and all associated support code and documentation.
2020-06-11 17:30:46 +01:00
Victor Stinner 51ae31e5b9
bpo-40684: Fix make install for platlibdir=lib64 (GH-20736)
"make install" now uses the PLATLIBDIR variable for the destination
lib-dynload/ directory when ./configure --with-platlibdir is used.

Update --with-platlibdir comment in configure.
2020-06-09 15:32:43 +02:00
Pablo Galindo d4fe098d1e
Python 3.10.0a0 (GH-20198) 2020-05-19 03:33:01 +01:00
Ned Deily 951ab58024
Revert "bpo-26317: Support OBJC and OBJCXX configure command line variables (GH-20176)" (GH-20182)
This reverts commit 0da5466650.

The commit is causing make failures on a FreeBSD buildbot.
Due to the imminent 3.9.0b1 cutoff, revert this commit for
now pending further investigation.
2020-05-18 11:31:21 -04:00
Ned Deily 0da5466650
bpo-26317: Support OBJC and OBJCXX configure command line variables (GH-20176)
Add support to the configure script for OBJC and OBJCXX command line options so that the macOS builds can use the clang compiler for the macOS-specific Objective C source files. This allows third-party compilers, like GNU gcc, to be used to build the rest of the project since some of the Objective C system header files are not compilable by GNU gcc.

Co-authored-by: Jeffrey Kintscher <websurfer@surf2c.net>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
2020-05-18 09:17:22 -04:00
Paul Ganssle 62972d9d73
bpo-40503: PEP 615: Tests and implementation for zoneinfo (GH-19909)
This is the initial implementation of PEP 615, the zoneinfo module,
ported from the standalone reference implementation (see
https://www.python.org/dev/peps/pep-0615/#reference-implementation for a
link, which has a more detailed commit history).

This includes (hopefully) all functional elements described in the PEP,
but documentation is found in a separate PR. This includes:

1. A pure python implementation of the ZoneInfo class
2. A C accelerated implementation of the ZoneInfo class
3. Tests with 100% branch coverage for the Python code (though C code
   coverage is less than 100%).
4. A compile-time configuration option on Linux (though not on Windows)

Differences from the reference implementation:

- The module is arranged slightly differently: the accelerated module is
  `_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates
  some changes in the test support function. (Suggested by Victor
  Stinner and Steve Dower.)
- The tests are arranged slightly differently and do not include the
  property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py
  rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py
  because we may do some refactoring in the future that would likely
  require this separation anyway; we may:
        - include the property tests
        - automatically run all the tests against both pure Python and C,
          rather than manually constructing C and Python test classes (similar
          to the way this works with test_datetime.py, which generates C
          and Python test cases from datetimetester.py).
- This includes a compile-time configuration option on Linux (though not
  on Windows); added with much help from Thomas Wouters.
- Integration into the CPython build system is obviously different from
  building a standalone zoneinfo module wheel.
- This includes configuration to install the tzdata package as part of
  CI, though only on the coverage jobs. Introducing a PyPI dependency as
  part of the CI build was controversial, and this is seen as less of a
  major change, since the coverage jobs already depend on pip and PyPI.

Additional changes that were introduced as part of this PR, most / all of
which were backported to the reference implementation:

- Fixed reference and memory leaks

    With much debugging help from Pablo Galindo

- Added smoke tests ensuring that the C and Python modules are built

    The import machinery can be somewhat fragile, and the "seamlessly falls
    back to pure Python" nature of this module makes it so that a problem
    building the C extension or a failure to import the pure Python version
    might easily go unnoticed.

- Adjustments to zoneinfo.__dir__

    Suggested by Petr Viktorin.

- Slight refactorings as suggested by Steve Dower.

- Removed unnecessary if check on std_abbr

    Discovered this because of a missing line in branch coverage.
2020-05-16 10:20:06 +02:00