[maccatalyst][coreclr] Fix native build failure on Xcode 26.2

[davidnguyen-tech]

Summary

Remove CMAKE_OSX_DEPLOYMENT_TARGET from the maccatalyst cmake args in eng/native/build-commons.sh.

Problem

Building for maccatalyst fails on Xcode 26.2 with:

clang: error: invalid version number in '-mmacosx-version-min=17.0'

The build sets CMAKE_SYSTEM_NAME=Darwin with CMAKE_OSX_SYSROOT=macosx, so CMake interprets CMAKE_OSX_DEPLOYMENT_TARGET=17.0 as a macOS deployment target and emits -mmacosx-version-min=17.0. But 17.0 is a Mac Catalyst version number, not a macOS version. Older clang accepted this silently; Xcode 26.2's clang rejects it as a hard error during CMake's compiler test, before configurecompiler.cmake can apply the correct -target arm64-apple-ios17.0-macabi triple.

Fix

Remove CMAKE_OSX_DEPLOYMENT_TARGET entirely. The value is not consumed — the effective Catalyst minimum version is enforced separately via the -target *-apple-ios<version>-macabi triple in eng/native/configurecompiler.cmake.

Validation

Full clr+clr.runtime+libs+packs build for maccatalyst-arm64 succeeds with this change on Xcode 26.2 / CMake 4.2.0.

[davidnguyen-tech]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull request overview

Removes an invalid macOS deployment target setting from the Mac Catalyst native CMake configuration to unblock builds on Xcode 26.2, where clang now hard-errors on -mmacosx-version-min=17.0.

Changes:

• Drop -DCMAKE_OSX_DEPLOYMENT_TARGET=17.0 from the maccatalyst CMake args so CMake’s compiler test uses a valid macOS min-version.
• Keep Mac Catalyst targeting driven by the explicit *-apple-ios17.0-macabi target triple applied later by configurecompiler.cmake.

[davidnguyen-tech]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

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[kotlarmilos]

Thanks @davidnguyen-tech. Is this failure encountered in the dotnet/dotnet build?

Having CMAKE_OSX_DEPLOYMENT_TARGET explicitly defined avoids unexpected behavior when the OS version changes. Could we set a new default minimum value?

[davidnguyen-tech]

Thanks @davidnguyen-tech. Is this failure encountered in the dotnet/dotnet build?

Having CMAKE_OSX_DEPLOYMENT_TARGET explicitly defined avoids unexpected behavior when the OS version changes. Could we set a new default minimum value?

I haven't tried it in dotnet/dotnet yet - only in dotnet/runtime.

Yes, setting a default minimum value makes sense. Thanks for suggestion.

[davidnguyen-tech]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[davidnguyen-tech]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[kotlarmilos]

Thanks!

[akoeplinger]

we should backport this to release/10.0 (maybe after giving it some time in main to uncover unforeseen issues)

[davidnguyen-tech]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[davidnguyen-tech]

/ba-g Everything builds on CI - subsequent failures are unrelated.