Compile error in MacOS

[Frank-AFN]

Env: MacOS Catalina (also tried in OS version MacOS High Serria)
Clang:

• Apple clang version 11.0.0 (clang-1100.0.33.8)
• Target: x86_64-apple-darwin19.0.0
• Thread model: posix
• InstalledDir: /Applications/Xcode11.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
  (also tried in clang version 10.0.1)

llvm: 7.1.0 (also tried in llvm version 9.0.0)

Compile Error:

Scanning dependencies of target hello-driver
[ 98%] Building CXX object tools/CMakeFiles/hello-driver.dir/hello_driver.cpp.o
In file included from /Users/zhangyy/CLionProjects/eos-vm/tools/hello_driver.cpp:1:
In file included from /Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/backend.hpp:3:
/Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/allocator.hpp:213:45: error: no member named 'extract' in 'std::__1::set<std::__1::pair<unsigned long, void *>, eosio::vm::jit_allocator::by_size,
std::__1::allocator<std::__1::pair<unsigned long, void *> > >'
auto node = free_blocks_by_size.extract({lhs->second, lhs->first});
~~~~~~~~~~~~~~~~~~~ ^
/Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/allocator.hpp:174:27: error: no member named 'extract' in 'std::__1::map<void *, unsigned long, std::__1::less<void *>, std::__1::allocator<std::__1::pair<void *const, unsigned long> >
>'
auto node = from.extract(key);
~~~~ ^
/Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/allocator.hpp:106:10: note: in instantiation of function template specialization 'eosio::vm::jit_allocator::transfer_node<std::__1::map<void *, unsigned long, std::__1::less<void *>,
std::__1::allocator<std::__1::pair<void *const, unsigned long> > > >' requested here
transfer_node(free_blocks, allocated_blocks, best->second);
^
/Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/allocator.hpp:174:27: error: no member named 'extract' in 'std::__1::set<std::__1::pair<unsigned long, void *>, eosio::vm::jit_allocator::by_size,
std::__1::allocator<std::__1::pair<unsigned long, void *> > >'
auto node = from.extract(key);
~~~~ ^
/Users/zhangyy/CLionProjects/eos-vm/include/eosio/vm/allocator.hpp:107:17: note: in instantiation of function template specialization 'eosio::vm::jit_allocator::transfer_node<std::__1::set<std::__1::pair<unsigned long, void *>,
eosio::vm::jit_allocator::by_size, std::__1::allocator<std::__1::pair<unsigned long, void *> > > >' requested here
best = transfer_node(free_blocks_by_size, allocated_blocks_by_size, *best);
^
3 errors generated.
make[2]: *** [tools/CMakeFiles/hello-driver.dir/hello_driver.cpp.o] Error 1
make[1]: *** [tools/CMakeFiles/hello-driver.dir/all] Error 2
make: *** [all] Error 2

It seems Clang does not support C++17 feature map and set extract function.

[peekpi]

1. download the latest libc++ source code from llvm
2. add the following code in 'eos-vm/CMakeLists.txt'
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostdinc++ -I <libcxx-install-prefix>/include")
3. recompile eos-vm