CI: Support older Arrow S3 packages

Probe ArrowS3 without requiring its package config so JNI builds continue to work with Arrow releases predating the S3 library split. Link the static target when it is available.

Author: xborder

dataset/CMakeLists.txt

@@ -18,7 +18,7 @@
 find_package(ArrowDataset REQUIRED)
 find_package(ArrowSubstrait REQUIRED)
 if(ARROW_S3)
-  find_package(ArrowS3 REQUIRED)
+  find_package(ArrowS3 QUIET)
 endif()
 
 include_directories(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
@@ -42,7 +42,7 @@ target_link_libraries(arrow_java_jni_dataset
                       jni
                       ArrowDataset::arrow_dataset_static
                       ArrowSubstrait::arrow_substrait_static)
-if(ARROW_S3)
+if(TARGET ArrowS3::arrow_s3_static)
   target_link_libraries(arrow_java_jni_dataset ArrowS3::arrow_s3_static)
 endif()