Use cross-platform build environment variables

…14)

14: Warn for raise with three compnents r=ltratt a=nanjekyejoannah

This makes sense at the AST hence isolated from the [other exception PR](softdevteam#12)

Co-authored-by: Joannah Nanjekye <jnanjekye@python.org>

16: Warn for specific thread module methods r=ltratt a=nanjekyejoannah

Dont merge until python#13  and  python#14 are merged, some helper code cuts across.

This replaces python#15 

Threading module Notes

Python 2:

```
>>> from thread import get_ident
>>> from threading import get_ident
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name get_ident
>>> import threading
>>> from threading import _get_ident
>>>
```

Python 3:

```
>>> from threading import get_ident
>>> from thread import get_ident
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'thread'
>
```

**Note:**

There is no neutral way of porting

Co-authored-by: Joannah Nanjekye <jnanjekye@python.org>

…ally (GH-14)

```
$ python3 --version && uname -a
Python 3.10.12
Linux ip-172-31-89-138 6.2.0-1014-aws python#14~22.04.1-Ubuntu SMP Thu Oct  5 22:43:45 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

$ echo AWS-LC PYTHON; echo; ./python bench/benchmarks.py; echo; echo SYSTEM PYTHON; echo; python3 bench/benchmarks.py
AWS-LC PYTHON

   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.000771021842956543
TLS        1024       0.0007800400257110595
TLS        1048576    0.0026435813903808595
md5        8          1.9125938415527344e-06
md5        1024       3.813743591308594e-06
md5        1048576    0.0019908883571624755
sha1       8          1.8870830535888672e-06
sha1       1024       3.3450126647949217e-06
sha1       1048576    0.001439645290374756
sha256     8          1.9631385803222656e-06
sha256     1024       5.374908447265625e-06
sha256     1048576    0.0034945359230041505
sha384     8          2.081632614135742e-06
sha384     1024       4.610776901245117e-06
sha384     1048576    0.002470192193984985
sha512     8          2.0771026611328124e-06
sha512     1024       4.634857177734375e-06
sha512     1048576    0.002472785234451294
sha3_256   8          2.4628639221191406e-06
sha3_256   1024       6.587982177734375e-06
sha3_256   1048576    0.0045334467887878415
sha3_384   8          2.4132728576660156e-06
sha3_384   1024       7.719039916992187e-06
sha3_384   1048576    0.005894896745681763
sha3_512   8          2.4335384368896486e-06
sha3_512   1024       1.061868667602539e-05
sha3_512   1048576    0.008451510906219482

SYSTEM PYTHON

   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.0019146842956542969
TLS        1024       0.0019197502136230468
TLS        1048576    0.00295937442779541
md5        8          1.884937286376953e-06
md5        1024       3.789663314819336e-06
md5        1048576    0.00199932861328125
sha1       8          1.8317699432373046e-06
sha1       1024       3.321409225463867e-06
sha1       1048576    0.0014382312297821045
sha256     8          2.0177364349365232e-06
sha256     1024       5.11932373046875e-06
sha256     1048576    0.003096806049346924
sha384     8          2.1207332611083983e-06
sha384     1024       4.274129867553711e-06
sha384     1048576    0.0020926313400268554
sha512     8          2.153873443603516e-06
sha512     1024       4.2979717254638674e-06
sha512     1048576    0.0020925924777984617
sha3_256   8          2.3796558380126953e-06
sha3_256   1024       5.854606628417969e-06
sha3_256   1048576    0.003778960466384888
sha3_384   8          2.38037109375e-06
sha3_384   1024       6.821155548095703e-06
sha3_384   1048576    0.004898728609085083
sha3_512   8          2.3713111877441406e-06
sha3_512   1024       9.174823760986328e-06
sha3_512   1048576    0.007007023334503174
```

```
$ python3 --version && uname -a
Python 3.10.12
Linux ip-172-31-89-138 6.2.0-1014-aws python#14~22.04.1-Ubuntu SMP Thu Oct  5 22:43:45 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

$ ./python bench/benchmarks.py; echo; python3 bench/benchmarks.py
OPENSSL VERSION: AWS-LC 1.19.0
   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.0007833797931671143
TLS        1024       0.0007857415676116944
TLS        1048576    0.002678983211517334
md5        8          1.9640922546386718e-06
md5        1024       3.949642181396484e-06
md5        1048576    0.0019850776195526124
sha1       8          1.847982406616211e-06
sha1       1024       3.45301628112793e-06
sha1       1048576    0.0014366722106933594
sha256     8          1.9931793212890624e-06
sha256     1024       5.559206008911133e-06
sha256     1048576    0.0035069866180419923
sha384     8          2.08735466003418e-06
sha384     1024       4.766225814819336e-06
sha384     1048576    0.0024656279087066652
sha512     8          2.061605453491211e-06
sha512     1024       4.767894744873047e-06
sha512     1048576    0.0024675443172454833
sha3_256   8          2.3877620697021486e-06
sha3_256   1024       6.785154342651367e-06
sha3_256   1048576    0.004528818607330322
sha3_384   8          2.38800048828125e-06
sha3_384   1024       7.86590576171875e-06
sha3_384   1048576    0.0058933842182159425
sha3_512   8          2.4230480194091797e-06
sha3_512   1024       1.0911941528320313e-05
sha3_512   1048576    0.008463276624679565

OPENSSL VERSION: OpenSSL 3.0.2 15 Mar 2022
   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.0018935666084289552
TLS        1024       0.0019144091606140136
TLS        1048576    0.0029557681083679198
md5        8          1.8961429595947266e-06
md5        1024       3.826141357421875e-06
md5        1048576    0.0019944441318511964
sha1       8          1.855611801147461e-06
sha1       1024       3.2887458801269532e-06
sha1       1048576    0.001434556007385254
sha256     8          1.9848346710205076e-06
sha256     1024       5.077362060546875e-06
sha256     1048576    0.003089451551437378
sha384     8          2.099514007568359e-06
sha384     1024       4.216670989990234e-06
sha384     1048576    0.0020866355895996095
sha512     8          2.0647048950195313e-06
sha512     1024       4.217624664306641e-06
sha512     1048576    0.002087009906768799
sha3_256   8          2.408742904663086e-06
sha3_256   1024       5.91588020324707e-06
sha3_256   1048576    0.0037849726676940916
sha3_384   8          2.4039745330810547e-06
sha3_384   1024       6.922245025634765e-06
sha3_384   1048576    0.004906209945678711
sha3_512   8          2.3734569549560547e-06
sha3_512   1024       9.36126708984375e-06
sha3_512   1048576    0.007021739959716797
```

```
$ python3 --version && uname -a
Python 3.10.12
Linux ip-172-31-89-138 6.2.0-1014-aws python#14~22.04.1-Ubuntu SMP Thu Oct  5 22:43:45 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

$ ./python bench/benchmarks.py; echo; python3 bench/benchmarks.py
OPENSSL VERSION: AWS-LC 1.19.0
   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.0007833797931671143
TLS        1024       0.0007857415676116944
TLS        1048576    0.002678983211517334
md5        8          1.9640922546386718e-06
md5        1024       3.949642181396484e-06
md5        1048576    0.0019850776195526124
sha1       8          1.847982406616211e-06
sha1       1024       3.45301628112793e-06
sha1       1048576    0.0014366722106933594
sha256     8          1.9931793212890624e-06
sha256     1024       5.559206008911133e-06
sha256     1048576    0.0035069866180419923
sha384     8          2.08735466003418e-06
sha384     1024       4.766225814819336e-06
sha384     1048576    0.0024656279087066652
sha512     8          2.061605453491211e-06
sha512     1024       4.767894744873047e-06
sha512     1048576    0.0024675443172454833
sha3_256   8          2.3877620697021486e-06
sha3_256   1024       6.785154342651367e-06
sha3_256   1048576    0.004528818607330322
sha3_384   8          2.38800048828125e-06
sha3_384   1024       7.86590576171875e-06
sha3_384   1048576    0.0058933842182159425
sha3_512   8          2.4230480194091797e-06
sha3_512   1024       1.0911941528320313e-05
sha3_512   1048576    0.008463276624679565

OPENSSL VERSION: OpenSSL 3.0.2 15 Mar 2022
   ALGO     SIZE (B)        TIME (s)
   ====     ========        ========
TLS        0          0.0018935666084289552
TLS        1024       0.0019144091606140136
TLS        1048576    0.0029557681083679198
md5        8          1.8961429595947266e-06
md5        1024       3.826141357421875e-06
md5        1048576    0.0019944441318511964
sha1       8          1.855611801147461e-06
sha1       1024       3.2887458801269532e-06
sha1       1048576    0.001434556007385254
sha256     8          1.9848346710205076e-06
sha256     1024       5.077362060546875e-06
sha256     1048576    0.003089451551437378
sha384     8          2.099514007568359e-06
sha384     1024       4.216670989990234e-06
sha384     1048576    0.0020866355895996095
sha512     8          2.0647048950195313e-06
sha512     1024       4.217624664306641e-06
sha512     1048576    0.002087009906768799
sha3_256   8          2.408742904663086e-06
sha3_256   1024       5.91588020324707e-06
sha3_256   1048576    0.0037849726676940916
sha3_384   8          2.4039745330810547e-06
sha3_384   1024       6.922245025634765e-06
sha3_384   1048576    0.004906209945678711
sha3_512   8          2.3734569549560547e-06
sha3_512   1024       9.36126708984375e-06
sha3_512   1048576    0.007021739959716797
```

Fix bug in specialization and make reification atomic

…at (python#14)

Move bytecode_offset=-1 initialization into hir_c_alloc_instr so the
invariant is structurally enforced — even if hir_c_init_instr is
accidentally skipped, bytecode_offset will be -1 (not 0 from calloc).

Add runtime regression test in hir_instr_c_verify.cpp that verifies
the invariant for all three allocation paths (raw alloc, init_instr,
init_deopt). Runs at startup via __attribute__((constructor)).

Addresses gap flagged 5 times (Pythia python#14, python#40, python#59, librarian x2).

exp-json/research now a self-contained fourth branch with 8 shipped
C-side optimisations in Modules/_json.c:
  E3 dispatch reorder, E5 raw PyObject** array, E1 single-pass
  classifier scan, E9 small-int parse, E10 cached ASCII separators,
  E11 writer size hint, E7 direct float-to-writer, E14 list-path
  separator extension.
Rejected E2 (manual decoder scan specialisation regressed by
1-2pp; compiler already auto-vectorises). Skipped E4 (roadmap
assumed per-instance memo; _default_decoder is already a module
singleton).

Results vs main (taskset-pinned, 21-run trimmed mean):
  web-api dumps     -13.2%
  log-line dumps    -15.8%
  NDJSON loads       -8.6%
  bulk dump 100k    -14.4%
  unicode ascii=F   -14.6%
  deep tree rt      -12.7%

Third-party smoke: simplejson / pydantic / jsonschema / fastapi
all produce identical output to main.

cpython-perf-ideas.md: struck python#14 (json key-memo LRU — moot)
and flagged the `_json.c` radar item as partially landed.

Bug python#14: phx_rc_env_block_state reallocs block_states array,
invalidating pred state pointers from collectPredStates.
Fix: allocate current block's state BEFORE collecting pred pointers.

Also add NULL/empty guard in initializeInState for predecessors
whose out-state hasn't been populated yet (backedge case).

Found via ASAN: heap-use-after-free in phx_sm_get called from
phx_rc_initialize_in_state. match/case pattern matching now compiles.