Riastradh has added additional runtime checks to the ctype functions, which are a libc feature that is commonly used incorrectly.
This includes guard page exploit mitigations.
https://freshbsd.org/netbsd/src/commit/FzouP6F1eaQTSROF
https://freshbsd.org/netbsd/src/commit/BCljW4bJuFO5QTOF