fix: add platform link deps for Arrow bundled S3 libraries in CMake config

When iceberg-cpp is built with ICEBERG_S3=ON using vendored Arrow,
arrow_bundled_dependencies contains the AWS SDK C libraries which
depend on platform-specific system libraries (CoreFoundation, Security,
Network on macOS; winhttp, bcrypt, etc. on Windows). Without declaring
these as transitive dependencies on the IMPORTED target, downstream
consumers get unresolved symbols at link time.

This mirrors Arrow's own ArrowConfig.cmake.in handling of the same
issue for aws-c-common bundled dependencies.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Sreesh Maheshwar

src/iceberg/iceberg-config.cmake.in

@@ -32,6 +32,7 @@
 @PACKAGE_INIT@
 
 set(ICEBERG_BUILD_STATIC "@ICEBERG_BUILD_STATIC@")
+set(ICEBERG_S3 "@ICEBERG_S3@")
 set(ICEBERG_SYSTEM_DEPENDENCIES "@ICEBERG_SYSTEM_DEPENDENCIES@")
 
 include(CMakeFindDependencyMacro)
@@ -93,6 +94,35 @@ if(TARGET iceberg::arrow_static)
                                      "${arrow_lib_dir}/${CMAKE_STATIC_LIBRARY_PREFIX}arrow_bundled_dependencies${CMAKE_STATIC_LIBRARY_SUFFIX}"
     )
   endforeach()
+
+  # When ICEBERG_S3 is enabled, Arrow's bundled static archive includes the
+  # AWS SDK C libraries (aws-c-common, etc.) which depend on platform-specific
+  # system libraries. Without these, downstream consumers get unresolved
+  # symbols at link time.
+  # Reference: Arrow's ArrowConfig.cmake.in handles this identically.
+  # https://github.com/apache/arrow/blob/main/cpp/src/arrow/ArrowConfig.cmake.in
+  if(ICEBERG_S3)
+    if(APPLE)
+      find_library(CORE_FOUNDATION CoreFoundation)
+      target_link_libraries(Arrow::arrow_bundled_dependencies
+                            INTERFACE ${CORE_FOUNDATION})
+      find_library(SECURITY Security)
+      target_link_libraries(Arrow::arrow_bundled_dependencies
+                            INTERFACE ${SECURITY})
+      find_library(NETWORK Network)
+      target_link_libraries(Arrow::arrow_bundled_dependencies INTERFACE ${NETWORK})
+    elseif(WIN32)
+      target_link_libraries(Arrow::arrow_bundled_dependencies
+                            INTERFACE "winhttp.lib"
+                                      "bcrypt.lib"
+                                      "wininet.lib"
+                                      "userenv.lib"
+                                      "version.lib"
+                                      "ncrypt.lib"
+                                      "Secur32.lib"
+                                      "Shlwapi.lib")
+    endif()
+  endif()
 endif()
 
 if(TARGET iceberg::parquet_static)