error: mac os x memory.h not found fix is not documented.

I did the following, which is not documented in your readme in this way; some steps still need to be completed.

## Installation of vcpkg
```
brew install vcpkg
git clone https://github.com/microsoft/vcpkg "$HOME/vcpkg"
export VCPKG_ROOT="$HOME/vcpkg"
export VCPKG_TOOLCHAIN_PATH $VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
echo $VCPKG_TOOLCHAIN_PATH # just to check
```

## Clone the repo with submodules

`git clone --recurse-submodules git@github.com:duckdb/extension-template.git`

## Run **make**, and generated an error:

```
Programming/Insight/extension-template/duckdb/src/include/duckdb/common/constants.hpp:11:10: fatal error: 'memory' file not found
11 | #include
| ^~~~~~~~
1 error generated.
make[3]: *** [src/verification/CMakeFiles/duckdb_verification.dir/copied_statement_verifier.cpp.o] Error 1
make[2]: *** [src/verification/CMakeFiles/duckdb_verification.dir/all] Error 2
make[1]: *** [all] Error 2
make: *** [release] Error 2
```

I added the path for the files, and it compiled.

`export CXXFLAGS="-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1"
`

I opened the issue because it is challenging to find/fix, and I thought you might like to add the info somewhere in your documentation.