Hello, As you may know, there has been a [new release of autoconf for the first time in 8 years](https://lists.gnu.org/archive/html/autoconf/2020-12/msg00002.html). Alas, building htslib with autoconf 2.70 currently fails. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=978835 Full build log is at http://qa-logs.debian.net/2020/09/26.ac270/htslib_1.10.2-5_unstable_ac270.log