erlang 23.0 doesn't build on macOS 11.0.1. This was originally reported to MacPorts.
The error is:
This is a lie. Your configure script is making an incorrect determination.
Your configure script is trying to check a computed value int_macosx_version against _ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED_. That preprocessor define will be a 4-digit number on OS X 10.9 and earlier, for example 1090 representing OS X 10.9 or 1050 representing Mac OS X 10.5, or a 6-digit number on OS X 10.10 and later, for example 101200 on macOS 10.12 or 110000 on macOS 11.0.
You are computing int_macosx_version incorrectly, doing it purely based on the pattern of digits in the version number. For macOS 11.0.1, you are computing the value 1101 when you should be computing the value 110001.
You committed an incorrect partial fix that may appear to fix the problem on macOS 11.0 but does not fix the problem on macOS 11.0.x and furthermore will give the wrong result on Mac OS X 10.y (where y is a single digit).