The attached patch to CMakeLists.txt fixes this by passing the UTC argument to the TIMESTAMP function.
According to my local tests, with this patch applied, and another patch soon to be submitted for embedded kernel versions, pgrouting should build reproducibly on tests.reproducible-builds.org!
Linux-5.18.0-0.deb11.4-amd64
vs.
Linux-5.10.0-18-amd64
The attached patch to src/version/version.h.in fixes this by using CMAKE_SYSTEM_NAME instead of CMAKE_SYSTEM.
According to my local tests, with this patch applied, and the patch submitted in #102179 to fix timestamps, pgrouting should build reproducibly on tests.reproducible-builds.org!
As reported in Debian Bug #1021799:
And Debian Bug #1021800:
@pgRouting/admins