Fails to build on MacOSX 15.4

[rfdougherty]

System Information
Please provide the following information about your system:

• Steam Audio version: 4.6.1
• Operating System and version: MacOS 15.4
• (Optional) CPU architecture (e.g. x86-64, armv7): arm64
• cmake version 4.0.1

Issue Description
Building dependencies fails.

Steps To Reproduce
Steps to reproduce the behavior:

1. git clone https://github.com/ValveSoftware/steam-audio.git
2. git checkout tags/v4.6.1
3. cd core/build
4. python3 get_dependencies.py --platform osx

This results in the following cmake error for deps flatbuffers, zlib, mysofa, and pffft:

CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.5 has been removed from CMake.

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.

  Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.

To fix this, I added this line to get_dependencies.py just after line 530:

cmake_args += ['-DCMAKE_POLICY_VERSION_MINIMUM=3.5']

This allowed cmake to build all the deps except zlib, which now fails with this error:

Command '['cmake', '--build', '/Users/bobd/git/steam-audio/core/deps-build/zlib/build/osx', '--config', 'Release', '--target', 'zlibstatic']' returned non-zero exit status 65.

which I believe is a result of this error:

In file included from steam-audio/core/deps-build/zlib/src/zlib/zutil.c:10:
In file included fromsteam-audio/core/deps-build/zlib/src/zlib/gzguts.h:21:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.4.sdk/usr/include/stdio.h:61:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.4.sdk/usr/include/_stdio.h:318:7: error: expected ')'
  318 | FILE    *fdopen(int, const char *) __DARWIN_ALIAS_STARTING(__MAC_10_6, __IPHONE_2_0, __DARWIN_ALIAS(fdopen));

[lakulish]

@rfdougherty This appears to be an issue with zlib, which was fixed in the following commit: madler/zlib@4bd9a71. I am updating dependencies.json to use the latest released version of zlib, which includes this commit, and builds successfully on macOS 15.4, using:

$ CMAKE_POLICY_VERSION_MINIMUM=3.5 python get_dependencies.py --platform osx