Problems installing pharo-launcher or pharo on RaspberryPi

Raspberry Pi 4.
       
I went to pharo.org/download

And downloaded both PharoLauncher-linux-2.0-x64.zip and pharo-linux-stable.zip.

I extracted them into separate directories.

I believe Pi 4 B is indeed 64 bit, but read somewhere that the Raspian installer installs a 32 bit O/S.
I would expect uname to tell me which.
It just says Linux pi 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux

Both of these these files extracted say the same thing when I try to run them:

64 bit:
pi@pi:~/Pharo/pharolauncher $ ./pharo-l*
Error. Could not determine platform's libc path for VM.
Try forcing $PLATFORMLIBDIR in /home/pi/Pharo/pharolauncher/pharo-vm/pharo, based on LIBC_SO.
Please report what works to pharo [vm-dev] mail list.
LIBC_SO=
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
UNAME=Linux pi 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux


 32 bit:
pi@pi:~/Pharo/32 bit/pharo-linux-stable/bin $ ./pharo
Error. Could not determine platform's libc path for VM.
Try forcing $PLATFORMLIBDIR in ./pharo, based on LIBC_SO.
Please report what works to pharo [vm-dev] mail list.
LIBC_SO=
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
UNAME=Linux pi 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux


Any clues?