unbundled jemalloc cannot be used, since it includes jemalloc_cpp.o that
contains new/delete overrides, so as clickhouse [1]:
ld.lld: error: duplicate symbol: operator delete(void*, unsigned long)
>>> defined at new_delete.cpp:147 (../src/Common/new_delete.cpp:147)
>>> new_delete.cpp.o:(operator delete(void*, unsigned long)) in archive src/libclickhouse_new_delete.a
>>> defined at jemalloc_cpp.o:(.text+0x160) in archive /usr/lib/x86_64-linux-gnu/libjemalloc.a
[1]: https://clickhouse-builds.s3.yandex.net/15828/35335f07dbf8cab89b4188a674b033c28409dc7b/clickhouse_build_check/build_log_793952627_1602401325.txt
INTERFACE_COMPILE_DEFINITIONS does not work IMPORTED targets:
From 3.6:
Specify compile definitions to use when compiling a given <target>.
The named <target> must have been created by a command such as
add_executable() or add_library() and must not be an Imported Target.
Since 3.11:
Specify compile definitions to use when compiling a given <target>.
The named <target> must have been created by a command such as
add_executable() or add_library() and must not be an ALIAS target.
And this causes the -Wundef warning:
src/Functions/FunctionsHashing.h:1326:5: warning: 'USE_XXHASH' is not defined, evaluates to 0 [-Wundef]
Since libstdc++ has some of such compares for 3way compare:
/src/ch/clickhouse/src/Common/UInt128.h:61:71: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]
bool inline operator>= (const UInt128 rhs) const { return tuple() >= rhs.tuple(); }
^~
nullptr
/usr/include/c++/10.2.0/tuple:1426:5: note: while rewriting comparison as call to 'operator<=>' declared here
operator<=>(const tuple<_Tps...>& __t, const tuple<_Ups...>& __u)
