arm64 R-devel builds use libedit instead of readline

FYI, in case this is not intended:

? otool -L /Library/Frameworks/R.framework/Versions/4.4-arm64/Resources/lib/libR.dylib
[...]
/usr/lib/libedit.3.dylib (compatibility version 2.0.0, current version 3.0.0)
[...]

x86_64 builds seem to use readline, still.

Gabor