makefiles/libc/picolibc.mk: only fail when building
makefiles/libc/picolibc.mk: only fail when building

ant9000/RIOT,OTAkeys/RIOT,miri64/RIOT,kaspar030/RIOT,OlegHahm/RIOT,authmillenon/RIOT,OlegHahm/RIOT,kYc0o/RIOT,kYc0o/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,jasonatran/RIOT,miri64/RIOT,ant9000/RIOT,kaspar030/RIOT,jasonatran/RIOT,authmillenon/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,kaspar030/RIOT,OTAkeys/RIOT,authmillenon/RIOT,miri64/RIOT,jasonatran/RIOT,jasonatran/RIOT,miri64/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,authmillenon/RIOT,authmillenon/RIOT,ant9000/RIOT,OTAkeys/RIOT,ant9000/RIOT,ant9000/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,kYc0o/RIOT