configure.ac: modernise

3 jobs for fixes in 39 minutes and 58 seconds (queued for 6 seconds)
Status Name Job ID Coverage
  Test
passed job_clang_amd64 #5784
amd64

00:39:58

passed job_clang_cxx_amd64 #5785
amd64

00:12:42

passed job_gcc_amd64 #5783
amd64

00:37:21