apple builds, supress deprecation warnings

[icing]

On apple builds, the gssapi/ldap/securetransport headers deprecate almost everything which leads to a wall of compiler warnings on use in code.

Suppress those warning that may hide other warnings/errors.

[testclutch]

Analysis of PR #15763 at 11cc7ccb:

Test 498 failed, which has NOT been flaky recently, so there could be a real issue in this PR.

Generated by Testclutch

[vszakats]

These warnings are annoying indeed. It's possible to silence them by setting a sufficiently low target version via -mmacosx-version-min= / -DCMAKE_OSX_DEPLOYMENT_TARGET= (details in .github/workflows/macos.yml). But, because Secure Transport requires a high version-min, it's not possible to avoid them with Secure Transport enabled together with GSS/LDAP.
I'm a little bit torn with this. Shouldn't we wait till May 2025, which will allow to solve this by setting a low target version (still to be done manually)? and/or by disabling the deprecated parts by default (or depending on target version, with some complexity)?
On the other hand existing warnings don't seem overly useful either, because these deprecated bits are still supported in latest macOS. Future deprecations might be useful, but curl doesn't use much Apple-specific APIs besides these.

I'm casually in favor, given the above.

If going with it, we might drop most if not all min-version logic and -Wno-deprecated-declarations use from GHA/macos.

[icing]

I think suppressing it in code via pragmas seems to solve the issues in a very simple way. I do not know of the target selection has other side effects.

[vszakats]

Agreed, it's the simplest, and unlikely the warnings will be missed by somebody.

Would you want to give a try to delete min-ver logic and -Wno-deprecated-declarations
from GHA/macos, and see which ones are still necessary after this patch?

edit: Hm, some of those (except 10.8/10.9) may have importance, so perhaps just go with dropping -Wno-deprecated-declarations in this patch and deal with the rest separately?

edit 2: relevant GHA code:

curl/.github/workflows/macos.yml

Lines 38 to 50 in fd067bf

	# Deprecated Apple APIs and the macos-version-min value required to avoid
	# deprecation warnings with llvm/clang:
	#
	# - 10.7 Lion (2011) - GSS
	# - 10.8 Mountain Lion (2012) - CFURLCreateDataAndPropertiesFromResource (used by curl Secure Transport code)
	# - 10.9 Maverick (2013) - LDAP
	# - 10.14 Mojave (2018) - Secure Transport
	#
	# For Secure Transport, curl implements features that require a target
	# newer than the 10.8 required by `CFURLCreateDataAndPropertiesFromResource`.
	# In this case `-Wno-deprecated-declarations` still comes handy to pacify
	# deprecation warnings, though the real solution would be to avoid calling
	# that function.

curl/.github/workflows/macos.yml

Line 121 in fd067bf

cflags: '-Wno-deprecated-declarations'

curl/.github/workflows/macos.yml

Line 253 in fd067bf

CFLAGS+=' ${{ matrix.build.cflags }}'

[icing]

Agreed, it's the simplest, and unlikely the warnings will be missed by somebody.

Would you want to give a try to delete min-ver logic and -Wno-deprecated-declarations from GHA/macos, and see which ones are still necessary after this patch?

I removed the -Wno-deprecated-declarations from the macos CI job. Lets see.