Preprocessor: fix compilation with GCC 10

11 jobs for master in 66 minutes and 28 seconds (queued for 36 seconds)
Status Job ID Name Coverage
  Build
passed #18392
build_binaries

00:12:46

passed #18393
build_doc

00:01:04

 
  Test And Pkg
passed #18396
macOS
pkg_macOS

00:12:47

passed #18394
pkg_source

00:01:29

passed #18395
pkg_windows

00:30:53

passed #18400
test_dynare++

00:11:41

passed #18397
test_matlab

00:52:38

manual #18399
allowed to fail manual
test_octave
manual #18398
allowed to fail manual
test_old_matlab
 
  Deploy
passed #18401
restricted
deploy_manual_unstable

00:00:18

passed #18402
restricted
deploy_snapshot_unstable

00:00:42