Set -e in iwyu.sh just before python script

cpp/build-support/iwyu/iwyu.sh

@@ -47,7 +47,7 @@ IWYU_ARGS="\
     --mapping_file=$IWYU_MAPPINGS_PATH/glog.imp \
     --mapping_file=$IWYU_MAPPINGS_PATH/gtest.imp"
 
-#PATH="$PATH:$PWD/../../thirdparty/clang-toolchain/bin"
+set -e
 python $ROOT/cpp/build-support/iwyu/iwyu_tool.py -p . $IWYU_FILE_LIST  -- \
      $IWYU_ARGS | awk -f $ROOT/cpp/build-support/iwyu/iwyu-filter.awk | \
      tee $IWYU_LOG

cpp/src/arrow/builder.cc

@@ -158,6 +158,7 @@ void ArrayBuilder::UnsafeSetNotNull(int64_t length) {
 
   // Fill up the bytes until we have a byte alignment
   int64_t pad_to_byte = std::min<int64_t>(8 - (length_ % 8), length);
+
   if (pad_to_byte == 8) {
     pad_to_byte = 0;
   }