Before adding this ignore you would receive the following when using GCC
7.3.1:
[ 82%] Building CXX object dbms/src/Storages/System/CMakeFiles/clickhouse_storages_system.dir/StorageSystemAsynchronousMetrics.cpp.o
In file included from /ClickHouse/dbms/src/Storages/System/StorageSystemAsynchronousMetrics.cpp:5:0:
/ClickHouse/dbms/src/Columns/ColumnString.h: In member function ‘virtual DB::BlockInputStreams DB::StorageSystemAsynchronousMetrics::read(const Names&, const DB::SelectQueryInfo&, const DB::Context&, DB::QueryProcessingStage::Enum&, size_t, unsigned int)’:
/ClickHouse/dbms/src/Columns/ColumnString.h:96:45: error: ‘*((void*)&<anonymous> +8)’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
const size_t size_to_append = s.size() + 1;
~~~~~~^~
cc1plus: all warnings being treated as errors
make[2]: *** [dbms/src/Storages/System/CMakeFiles/clickhouse_storages_system.dir/build.make:63: dbms/src/Storages/System/CMakeFiles/clickhouse_storages_system.dir/StorageSystemAsynchronousMetrics.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:9105: dbms/src/Storages/System/CMakeFiles/clickhouse_storages_system.dir/all] Error 2
make: *** [Makefile:163: all] Error 2
