Symlink Google Drive
You can use a directory hard link, but only on HFS+ file system. You'll need GNU ln to use the -d option. This can be installed using Homebrew: brew install coreutils, then run:

sudo gln -d "/path/to/original" "/path/to/drive/folder"


You will be asked for your password. This command creates a hard link to the file/folder itself rather than how a symlink links to a pointer to a file/dir. As the link folder is essentially the same as the original folder, Google Drive syncs it correctly.

To unlink a hard link, use unlink "/path/to/drive/folder".

WARNING: APFS (Apple File System) does not support hard links. If you plan on installing macOS High Sierra or later and want to continue using directory hard links, you will need to maintain your HFS+ file system. By default macOS High Sierra intaller on a mac with SSD (e.g. without HDD or Fusion Drive) automatically converts HFS+ filesystem to APFS. To skip conversion during upgrade you will need to run the macOS installer as follows: 

/Applications/Install\ macOS\ High\ Sierra.app/*/R*/startosinstall --converttoapfs NO


If you avoid the last option you will end up with mess of hard linked dirs in /.HFS+ Private Directory Data after the the upgrade.