Diff of the two buildlogs:

--
--- b1/build.log	2025-03-01 11:31:03.664189104 +0000
+++ b2/build.log	2025-03-01 11:31:53.085949820 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Fri Feb 28 23:29:58 -12 2025
-I: pbuilder-time-stamp: 1740828598
+I: Current time: Sat Apr  4 07:54:05 +14 2026
+I: pbuilder-time-stamp: 1775238845
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/unstable-reproducible-base.tgz]
 I: copying local configuration
@@ -25,52 +25,84 @@
 dpkg-source: info: applying remove-hs-macro.patch
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/3320587/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/2409075/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos5-amd64.
+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 Apr  3 17:54 /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/2409075/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/2409075/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='amd64'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=20 '
-  DISTRIBUTION='unstable'
-  HOME='/root'
-  HOST_ARCH='amd64'
+  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]="x86_64-pc-linux-gnu")
+  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=amd64
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=42 '
+  DIRSTACK=()
+  DISTRIBUTION=unstable
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=x86_64
+  HOST_ARCH=amd64
   IFS=' 	
   '
-  INVOCATION_ID='db908a194f2844468789f66a29f7f64e'
-  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='3320587'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=31fea6f7cc4748878c02962d2b821e22
+  LANG=C
+  LANGUAGE=et_EE:et
+  LC_ALL=C
+  MACHTYPE=x86_64-pc-linux-gnu
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnu
+  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=2409075
   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.6FnIVruI/pbuilderrc_SiuL --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.6FnIVruI/b1 --logfile b1/build.log tcl-unix-sockets_0.5-3.dsc'
-  SUDO_GID='110'
-  SUDO_UID='105'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://46.16.76.132:3128'
+  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.6FnIVruI/pbuilderrc_SmUC --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.6FnIVruI/b2 --logfile b2/build.log tcl-unix-sockets_0.5-3.dsc'
+  SUDO_GID=110
+  SUDO_UID=105
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://213.165.73.152:3128
 I: uname -a
-  Linux ionos1-amd64 6.1.0-31-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.128-1 (2025-02-07) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.12.9+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.9-1~bpo12+1 (2025-01-19) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/3320587/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/2409075/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: 35 http://deb.debian.org/debian unstable/main amd64 zlib1g-dev amd64 1:1.3.dfsg+really1.3.1-1+b1 [920 kB]
 Get: 36 http://deb.debian.org/debian unstable/main amd64 tcl8.6-dev amd64 8.6.16+dfsg-1 [1032 kB]
 Get: 37 http://deb.debian.org/debian unstable/main amd64 tcl-dev amd64 8.6.14 [6580 B]
-Fetched 23.9 MB in 2s (14.1 MB/s)
+Fetched 23.9 MB in 0s (72.6 MB/s)
 Preconfiguring packages ...
 Selecting previously unselected package tzdata.
 (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 ... 19780 files and directories currently installed.)
@@ -273,8 +305,8 @@
 Setting up tzdata (2025a-2) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Sat Mar  1 11:30:46 UTC 2025.
-Universal Time is now:  Sat Mar  1 11:30:46 UTC 2025.
+Local time is now:      Fri Apr  3 17:54:35 UTC 2026.
+Universal Time is now:  Fri Apr  3 17:54:35 UTC 2026.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up autotools-dev (20220109.1) ...
@@ -314,7 +346,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/tcl-unix-sockets-0.5/ && 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  > ../tcl-unix-sockets_0.5-3_source.changes
+I: user script /srv/workspace/pbuilder/2409075/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for unstable
+I: user script /srv/workspace/pbuilder/2409075/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/tcl-unix-sockets-0.5/ && 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  > ../tcl-unix-sockets_0.5-3_source.changes
 dpkg-buildpackage: info: source package tcl-unix-sockets
 dpkg-buildpackage: info: source version 0.5-3
 dpkg-buildpackage: info: source distribution unstable
@@ -339,7 +375,7 @@
 	./configure --build=x86_64-linux-gnu --prefix=/usr --includedir=\${prefix}/include --mandir=\${prefix}/share/man --infodir=\${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-option-checking --disable-silent-rules --libdir=\${prefix}/lib/x86_64-linux-gnu --runstatedir=/run --disable-maintainer-mode --disable-dependency-tracking --with-tcl=/usr/lib/tcl8.6 --prefix=/usr --libdir=/usr/lib/tcltk/x86_64-linux-gnu --libexecdir=/usr/lib/tcltk/x86_64-linux-gnu
 checking TEA configuration... ok (TEA 3.13)
 configure: configuring unix_sockets 0.5
-checking system version... Linux-6.1.0-31-amd64
+checking system version... Linux-6.12.9+bpo-amd64
 checking for Tcl configuration... found /usr/lib/tcl8.6/tclConfig.sh
 checking for gcc... gcc
 checking whether the C compiler works... yes
@@ -380,7 +416,7 @@
 checking if 64bit Sparc VIS support is requested... no
 checking if compiler supports visibility "hidden"... yes
 checking if rpath support is requested... yes
-checking system version... (cached) Linux-6.1.0-31-amd64
+checking system version... (cached) Linux-6.12.9+bpo-amd64
 checking for ar... ar
 checking for cast to union support... yes
 checking for stdbool.h... yes
@@ -396,7 +432,7 @@
 config.status: creating generic/config.h
 make[1]: Leaving directory '/build/reproducible-path/tcl-unix-sockets-0.5'
    dh_auto_build
-	make -j20
+	make -j42
 make[1]: Entering directory '/build/reproducible-path/tcl-unix-sockets-0.5'
 gcc -DPACKAGE_NAME=\"unix_sockets\" -DPACKAGE_TARNAME=\"unix_sockets\" -DPACKAGE_VERSION=\"0.5\" -DPACKAGE_STRING=\"unix_sockets\ 0.5\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DBUILD_unix_sockets=/\*\*/ -DHAVE_STDIO_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_UNISTD_H=1 -DSTDC_HEADERS=1 -DUSE_THREAD_ALLOC=1 -D_REENTRANT=1 -D_THREAD_SAFE=1 -DTCL_THREADS=1 -DUSE_TCL_STUBS=1 -DUSE_TCLOO_STUBS=1 -DMODULE_SCOPE=extern\ __attribute__\(\(__visibility__\(\"hidden\"\)\)\) -DHAVE_HIDDEN=1 -DHAVE_CAST_TO_UNION=1 -DHAVE_STDBOOL_H=1 -D_LARGEFILE64_SOURCE=1 -DTCL_WIDE_INT_IS_LONG=1 -DTCL_CFG_OPTIMIZED=1 -DUSE_TCL_STUBS=1 -DTCL_MAJOR_VERSION=8  -I"/usr/include/tcl8.6"    -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/tcl-unix-sockets-0.5=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wall -pedantic -I/usr/include/tcl -pipe -O2 -fomit-frame-pointer -DNDEBUG -Wall -fPIC -Wdate-time -D_FORTIFY_SOURCE=2  -c `echo ./generic/main.c` -o main.o
 If you have documentation to create, place the commands to
@@ -412,13 +448,13 @@
    debian/rules override_dh_auto_install
 make[1]: Entering directory '/build/reproducible-path/tcl-unix-sockets-0.5'
 dh_auto_install
-	make -j20 install DESTDIR=/build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets AM_UPDATE_INFO_DIR=no
+	make -j42 install DESTDIR=/build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets AM_UPDATE_INFO_DIR=no
 make[2]: Entering directory '/build/reproducible-path/tcl-unix-sockets-0.5'
 If you have documentation to create, place the commands to
 build the docs in the 'doc:' target.  For example:
-        xml2nroff sample.xml > sample.n
- /bin/bash ./tclconfig/install-sh -c -m 755 libunix_sockets0.5.so /build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets/usr/lib/tcltk/x86_64-linux-gnu/unix_sockets0.5/libunix_sockets0.5.so
+ /bin/sh ./tclconfig/install-sh -c -m 755 libunix_sockets0.5.so /build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets/usr/lib/tcltk/x86_64-linux-gnu/unix_sockets0.5/libunix_sockets0.5.so
 Installing header files in /build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets/usr/include
+        xml2nroff sample.xml > sample.n
         xml2html sample.xml > sample.html
 Installing documentation in /build/reproducible-path/tcl-unix-sockets-0.5/debian/tcl-unix-sockets/usr/share/man
 Installing ./doc/unix_sockets.n
@@ -467,12 +503,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: not including original source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/2409075/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/2409075/tmp/hooks/B01_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/3320587 and its subdirectories
-I: Current time: Fri Feb 28 23:31:03 -12 2025
-I: pbuilder-time-stamp: 1740828663
+I: removing directory /srv/workspace/pbuilder/2409075 and its subdirectories
+I: Current time: Sat Apr  4 07:54:52 +14 2026
+I: pbuilder-time-stamp: 1775238892