[advitrocks9]

On macOS, configure sets LIBFFI_CFLAGS and LIBFFI_LIBS from the SDK before the pkg-config
check, so values passed on the command line are ignored. Doc/using/configure.rst documents both
as overrides. This uses the same preserve-if-set form as the pkg-config fallback and the libuuid
probe.

Configuring with LIBFFI_CFLAGS=-I/nonexistent/include/ffi LIBFFI_LIBS="-L/nonexistent/lib -lffi",
the Makefile currently ends up with the SDK paths:

MODULE__CTYPES_CFLAGS=-fno-strict-overflow -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/ffi -DUSING_APPLE_OS_LIBFFI=1 -DUSING_MALLOC_CLOSURE_DOT_C=1
MODULE__CTYPES_LDFLAGS=-lffi -ldl

and with this change keeps the given values:

MODULE__CTYPES_CFLAGS=-fno-strict-overflow -I/nonexistent/include/ffi -DUSING_MALLOC_CLOSURE_DOT_C=1
MODULE__CTYPES_LDFLAGS=-L/nonexistent/lib -lffi -ldl

With no overrides the output is unchanged. USING_APPLE_OS_LIBFFI drops out when overriding
since it guards Apple-libffi code in _ctypes. iOS sets a different ac_sys_system and is
unaffected. The other documented *_CFLAGS/*_LIBS pairs already preserve user values.

• Issue: macOS: configure does not support linking against a non-system libffi #155813

[freakboy3742]

Makes sense - thanks for the patch!

[miss-islington-app]

Thanks @advitrocks9 for the PR, and @freakboy3742 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-160129 is a backport of this pull request to the 3.15 branch.

[bedevere-app]

GH-160130 is a backport of this pull request to the 3.14 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 FreeBSD16 3.15 (tier-3) has failed when building commit 56c0185.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/2103/builds/220) and take a look at the build logs.
4. Check if the failure is related to this commit (56c0185) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/2103/builds/220

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.15.opsec-fbsd16/build/Lib/test/support/__init__.py", line 949, in gc_collect
    gc.collect()
    ~~~~~~~~~~^^
ResourceWarning: unclosed <socket.socket fd=8, family=2, type=1, proto=6, laddr=('127.0.0.1', 23055), raddr=('127.0.0.1', 47683)>
Warning -- Unraisable exception
Exception ignored while calling deallocator <function _SelectorTransport.__del__ at 0x8c6301abe90>:
Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.15.opsec-fbsd16/build/Lib/asyncio/selector_events.py", line 879, in __del__
    _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ResourceWarning: unclosed transport <_SelectorSocketTransport closing fd=8>
k


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.15.opsec-fbsd16/build/Lib/test/support/__init__.py", line 949, in gc_collect
    gc.collect()
    ~~~~~~~~~~^^
ResourceWarning: unclosed <socket.socket fd=8, family=2, type=1, proto=6, laddr=('127.0.0.1', 58229), raddr=('127.0.0.1', 23622)>
Warning -- Unraisable exception
Exception ignored while calling deallocator <function _SelectorTransport.__del__ at 0x34b28ecb6510>:
Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.15.opsec-fbsd16/build/Lib/asyncio/selector_events.py", line 879, in __del__
    _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ResourceWarning: unclosed transport <_SelectorSocketTransport closing fd=8>
k