Diff of the two buildlogs:

--
--- b1/build.log	2025-01-28 03:43:42.131887539 +0000
+++ b2/build.log	2025-01-28 03:58:18.828206343 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Mon Jan 27 15:23:45 -12 2025
-I: pbuilder-time-stamp: 1738034625
+I: Current time: Tue Jan 28 17:43:50 +14 2025
+I: pbuilder-time-stamp: 1738035830
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/unstable-reproducible-base.tgz]
 I: copying local configuration
@@ -20,52 +20,84 @@
 dpkg-source: info: unpacking shellia_5.9.tar.xz
 I: using fakeroot in build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/30243/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/D01_modify_environment starting
+debug: Running on virt64a.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Jan 28 03:44 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='armhf'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=3 '
-  DISTRIBUTION='unstable'
-  HOME='/root'
-  HOST_ARCH='armhf'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="37" [3]="1" [4]="release" [5]="arm-unknown-linux-gnueabihf")
+  BASH_VERSION='5.2.37(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=armhf
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=4 '
+  DIRSTACK=()
+  DISTRIBUTION=unstable
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=arm
+  HOST_ARCH=armhf
   IFS=' 	
   '
-  INVOCATION_ID='f881f41521554b0a8a915090d5d22523'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='30243'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=2f08ef4efe9c4f0f92c071939e578916
+  LANG=C
+  LANGUAGE=it_CH:it
+  LC_ALL=C
+  MACHTYPE=arm-unknown-linux-gnueabihf
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnueabihf
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=12385
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.XXHmiPgn/pbuilderrc_nMOv --distribution unstable --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.XXHmiPgn/b1 --logfile b1/build.log shellia_5.9.dsc'
-  SUDO_GID='110'
-  SUDO_UID='103'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://10.0.0.15:3142/'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.XXHmiPgn/pbuilderrc_BvHm --distribution unstable --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.XXHmiPgn/b2 --logfile b2/build.log shellia_5.9.dsc'
+  SUDO_GID=114
+  SUDO_UID=108
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://10.0.0.15:3142/
 I: uname -a
-  Linux virt32z 6.1.0-30-armmp-lpae #1 SMP Debian 6.1.124-1 (2025-01-12) armv7l GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-30-arm64 #1 SMP Debian 6.1.124-1 (2025-01-12) aarch64 GNU/Linux
 I: ls -l /bin
   lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/30243/tmp/hooks/D02_print_environment finished
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -145,7 +177,7 @@
 Get: 28 http://deb.debian.org/debian unstable/main armhf m4 armhf 1.4.19-5 [272 kB]
 Get: 29 http://deb.debian.org/debian unstable/main armhf autoconf all 2.72-3 [493 kB]
 Get: 30 http://deb.debian.org/debian unstable/main armhf autotools-dev all 20220109.1 [51.6 kB]
-Get: 31 http://deb.debian.org/debian unstable/main armhf automake all 1:1.17-2 [861 kB]
+Get: 31 http://deb.debian.org/debian unstable/main armhf automake all 1:1.17-1 [861 kB]
 Get: 32 http://deb.debian.org/debian unstable/main armhf autopoint all 0.23.1-1 [770 kB]
 Get: 33 http://deb.debian.org/debian unstable/main armhf bc armhf 1.07.1-4 [97.8 kB]
 Get: 34 http://deb.debian.org/debian unstable/main armhf busybox armhf 1:1.37.0-4 [475 kB]
@@ -171,7 +203,7 @@
 Get: 54 http://deb.debian.org/debian unstable/main armhf python3-roman all 4.2-1 [10.4 kB]
 Get: 55 http://deb.debian.org/debian unstable/main armhf python3-docutils all 0.21.2+dfsg-2 [403 kB]
 Get: 56 http://deb.debian.org/debian unstable/main armhf time armhf 1.9-0.2 [50.9 kB]
-Fetched 28.3 MB in 2s (11.5 MB/s)
+Fetched 28.3 MB in 0s (57.1 MB/s)
 Preconfiguring packages ...
 Selecting previously unselected package readline-common.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19568 files and directories currently installed.)
@@ -279,8 +311,8 @@
 Preparing to unpack .../14-autotools-dev_20220109.1_all.deb ...
 Unpacking autotools-dev (20220109.1) ...
 Selecting previously unselected package automake.
-Preparing to unpack .../15-automake_1%3a1.17-2_all.deb ...
-Unpacking automake (1:1.17-2) ...
+Preparing to unpack .../15-automake_1%3a1.17-1_all.deb ...
+Unpacking automake (1:1.17-1) ...
 Selecting previously unselected package autopoint.
 Preparing to unpack .../16-autopoint_0.23.1-1_all.deb ...
 Unpacking autopoint (0.23.1-1) ...
@@ -375,8 +407,8 @@
 Setting up tzdata (2025a-1) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Tue Jan 28 03:24:23 UTC 2025.
-Universal Time is now:  Tue Jan 28 03:24:23 UTC 2025.
+Local time is now:      Tue Jan 28 03:45:21 UTC 2025.
+Universal Time is now:  Tue Jan 28 03:45:21 UTC 2025.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up busybox (1:1.37.0-4) ...
@@ -395,7 +427,7 @@
 Setting up libpython3.13-stdlib:armhf (3.13.1-3) ...
 Setting up libxml2:armhf (2.12.7+dfsg+really2.9.14-0.2+b1) ...
 Setting up libpython3-stdlib:armhf (3.13.1-2) ...
-Setting up automake (1:1.17-2) ...
+Setting up automake (1:1.17-1) ...
 update-alternatives: using /usr/bin/automake-1.17 to provide /usr/bin/automake (automake) in auto mode
 Setting up libfile-stripnondeterminism-perl (1.14.1-1) ...
 Setting up gettext (0.23.1-1) ...
@@ -431,7 +463,11 @@
 fakeroot is already the newest version (1.37-1).
 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
 I: Building the package
-I: Running cd /build/reproducible-path/shellia-5.9/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../shellia_5.9_source.changes
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for unstable
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/shellia-5.9/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../shellia_5.9_source.changes
 dpkg-buildpackage: info: source package shellia
 dpkg-buildpackage: info: source version 5.9
 dpkg-buildpackage: info: source distribution unstable
@@ -441,7 +477,7 @@
  fakeroot debian/rules clean
 dh clean
    dh_auto_clean
-	make -j3 clean
+	make -j4 clean
 make[1]: Entering directory '/build/reproducible-path/shellia-5.9'
 make[1]: Leaving directory '/build/reproducible-path/shellia-5.9'
    dh_clean
@@ -451,7 +487,7 @@
    dh_autoreconf
    dh_auto_configure
    dh_auto_build
-	make -j3 "INSTALL=install --strip-program=true"
+	make -j4 "INSTALL=install --strip-program=true"
 make[1]: Entering directory '/build/reproducible-path/shellia-5.9'
 INFO: sshd2222: ssh is not installed
 OK "./tests/test.backslash" -s "bash"
@@ -630,7 +666,17 @@
 OK "./tests/test.multiply" -s "bash"
 OK "./tests/test.multiply" -s "dash"
 OK "./tests/test.multiply" -s "busybox sh"
-OK "./tests/test.multiply" -s "mksh"
+ERROR (5) "./tests/test.multiply" -s "mksh" / shortened difference between expectation and result:
+   1,15c1,15
+   < + mult 3 2
+   < + local ret
+   < + ret=0
+   < + plus 0 2
+   < + echo 2
+   < + ret=2
+   < + plus 2 2
+   < + echo 4
+   < + ret=4
 OK "./tests/test.multiply" -s "posh"
 WARN "./tests/test.mylib" -s "bash" => no test, because sshd2222 is not possible
 WARN "./tests/test.mylib" -s "dash" => no test, because sshd2222 is not possible
@@ -676,7 +722,17 @@
 OK "./tests/test.return" -s "bash"
 OK "./tests/test.return" -s "dash"
 OK "./tests/test.return" -s "busybox sh"
-OK "./tests/test.return" -s "mksh"
+ERROR (3) "./tests/test.return" -s "mksh" / shortened difference between expectation and result:
+   1,2c1,2
+   < + :
+   < + echo return=<0>
+   ---
+   > ++ :
+   > ++ echo return=<0>
+   4,7c4,7
+   < + fun1 42
+   < + echo msg1 on stdout
+   < + echo msg2 on stderr
 OK "./tests/test.return" -s "posh"
 OK "./tests/test.return2" -s "bash"
 OK "./tests/test.return2" -s "dash"
@@ -759,49 +815,24 @@
 OK "./tests/test.wrong-missing-ia_init" -s "mksh"
 OK "./tests/test.wrong-missing-ia_init" -s "posh"
 INFO: sshd2222: ssh is not installed
-0 Errors
+2 Errors
+make[1]: *** [Makefile:29: shellia-tested-stamp] Error 2
 make[1]: Leaving directory '/build/reproducible-path/shellia-5.9'
-   dh_auto_test
-   create-stamp debian/debhelper-build-stamp
- fakeroot debian/rules binary
-dh binary
-   dh_testroot
-   dh_prep
-   dh_auto_install --destdir=debian/shellia/
-	make -j3 install DESTDIR=/build/reproducible-path/shellia-5.9/debian/shellia AM_UPDATE_INFO_DIR=no "INSTALL=install --strip-program=true"
-make[1]: Entering directory '/build/reproducible-path/shellia-5.9'
-make[1]: Leaving directory '/build/reproducible-path/shellia-5.9'
-   dh_installdocs
-   dh_installchangelogs
-   dh_installexamples
-   dh_installman
-   dh_perl
-   dh_link
-   dh_strip_nondeterminism
-   debian/rules override_dh_compress
-make[1]: Entering directory '/build/reproducible-path/shellia-5.9'
-dh_compress -X examples/mylib
-make[1]: Leaving directory '/build/reproducible-path/shellia-5.9'
-   dh_fixperms
-   dh_missing
-   dh_installdeb
-   dh_gencontrol
-   dh_md5sums
-   dh_builddeb
-dpkg-deb: building package 'shellia' in '../shellia_5.9_all.deb'.
- dpkg-genbuildinfo --build=binary -O../shellia_5.9_armhf.buildinfo
- dpkg-genchanges --build=binary -O../shellia_5.9_armhf.changes
-dpkg-genchanges: info: binary-only upload (no source code included)
- dpkg-source --after-build .
-dpkg-buildpackage: info: binary-only upload (no source included)
-dpkg-genchanges: info: including full source code in upload
+dh_auto_build: error: make -j4 "INSTALL=install --strip-program=true" returned exit code 2
+make: *** [debian/rules:19: build] Error 25
+dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
 I: copying local configuration
+E: Failed autobuilding of package
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/C01_cleanup starting
+debug output: disk usage on i-capture-the-hostname at Tue Jan 28 03:58:12 UTC 2025
+Filesystem      Size  Used Avail Use% Mounted on
+tmpfs           6.2G     0  6.2G   0% /dev/shm
+
+I: user script /srv/workspace/pbuilder/12385/tmp/hooks/C01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/30243 and its subdirectories
-I: Current time: Mon Jan 27 15:43:38 -12 2025
-I: pbuilder-time-stamp: 1738035818
+I: removing directory /srv/workspace/pbuilder/12385 and its subdirectories