Installing Rserve 1.8-6 on macOS 10.15. (Catalina)

I’m on a different computer than before, and tried to get the R snippets working in Knime. I remember that this was already quite difficult on macOS 10.14 (Mojave), however now I have the feeling that it seems impossible on macOS 10.15 (Catalina). I have installed and reinstalled Xcode, and the commandline tools (also separately). Additionally XQuartz, Clang and GNU Fortran have also been installed. Along with several Warnings, when trying to install (using the “R CMD INSTALL Rserve_1.8-6.tar.gz” in Terminal) I also get following error:

clang -Wall -g -O2 -DTHREADSAFE -pthread -o forward forward.o http.o http_tools.o server.o tls.o websockets.o md5.o sha1.o base64.o date.o ulog.o chandler.o rscript.o -ldl -lssl

ld: library not found for -lssl

clang: error: linker command failed with exit code 1 (use -v to see invocation)

make[1]: * [forward] Error 1

make: * [all] Error 2

ERROR: compilation failed for package ‘Rserve’

*

removing ‘/Library/Frameworks/R.framework/Versions/3.6/Resources/library/Rserve’

*

restoring previous ‘/Library/Frameworks/R.framework/Versions/3.6/Resources/library/Rserve’

As the error seems to be related to the ssl library, I have additionally installed a brew version of OpenSSL which did not help either… I have also looked into doing following:

sudo installer -pkg \ /Library/Developer/CommandLineTools/Packages/macOSSDKheadersformacOS_10.14.pkg \ -target

however, on macOS_10.15 there is no Packages folder any longer…

Has anyone successfully installed Rserve on a Mac running 10.15, or does anyone have any further suggestions?

Cheers, Sebastian