shiftNegativeLHS
ftp://ftp.de.debian.org/debian/pool/main/p/proj/proj_9.8.1.orig.tar.gz
2.21.0 proj-9.8.1/src/projections/isea.cpp:869:24: portability: Shifting a negative value is technically undefined behaviour [shiftNegativeLHS]
ftp://ftp.de.debian.org/debian/pool/main/r/rcpp/rcpp_1.1.2.orig.tar.gz
2.21.0 Rcpp/src/date.cpp:484:30: portability: Shifting a negative value is technically undefined behaviour [shiftNegativeLHS]
2.21.0 Rcpp/src/date.cpp:491:30: portability: Shifting a negative value is technically undefined behaviour [shiftNegativeLHS]