All actual, nothing to do with that. Your response and this: https://unix.stackexchange.com/a/44167 gave me a hunch. I had MAKEFLAGS=--no-print-directory -e in my .profile... and ran zypper from su resp. yast2 from the user session. I propose to put a hint into the docs saying e.g: "Please ensure to start zypper with a clean environment without user settings changing the behavior of system tools like make, grep, ls." Thanks for the quick reaction and please apologize the trouble...