fix(deps): disable Assimp bundled zlib on macOS to fix build with SDK 15+

Assimp 5.4.3's bundled zlib defines `#define fdopen(fd,mode) NULL` in
contrib/zlib/zutil.h:147. On macOS 15+ the SDK's `_stdio.h` uses
`__DARWIN_ALIAS(fdopen)`, which expands through that macro and causes a
C preprocessor parse error, breaking the "Build Deps" CI step on both
arm64 and x86_64.

Fix: only build the bundled zlib on Windows (where it is needed);
on macOS and Linux use the system-provided zlib instead.

Fixes the CI failures in #10767.

Co-Authored-By: Abdel Gomez-Perez <nabdel07@icloud.com>

Author: BenJule

deps/Assimp/Assimp.cmake

@@ -1,3 +1,12 @@
+if (WIN32)
+    set(_assimp_build_zlib ON)
+else ()
+    # On macOS the bundled zlib's fdopen() macro conflicts with the macOS 15+ SDK
+    # __DARWIN_ALIAS(fdopen) expansion, causing a parse error during dep builds.
+    # System zlib is always available on macOS/Linux, so disable the bundled copy.
+    set(_assimp_build_zlib OFF)
+endif ()
+
 bambustudio_add_cmake_project(Assimp
     URL "https://github.com/assimp/assimp/archive/refs/tags/v5.4.3.tar.gz"
     URL_HASH SHA256=66dfbaee288f2bc43172440a55d0235dfc7bf885dda6435c038e8000e79582cb
@@ -11,7 +20,7 @@ bambustudio_add_cmake_project(Assimp
         -DASSIMP_BUILD_GLTF_IMPORTER=ON
         -DASSIMP_BUILD_OBJ_IMPORTER=ON
         -DASSIMP_BUILD_FBX_IMPORTER=ON
-        -DASSIMP_BUILD_ZLIB=ON
+        -DASSIMP_BUILD_ZLIB=${_assimp_build_zlib}
         -DASSIMP_WARNINGS_AS_ERRORS=OFF
         -DBUILD_WITH_STATIC_CRT=OFF
 )