Looking at the build log in the linked Debian issue, there is an argument setting -std=c++11. It seems as though an implicit inclusion of <cstdint> had been provided by libstdc++ in the past and was removed as of GCC 15.

https://github.com/bpftrace/bpftrace/pull/3407

https://gcc.gnu.org/pipermail/gcc-patches/2024-August/659176...

Looks like they did in fact add the header detail to the porting guide:

https://gcc.gnu.org/gcc-15/porting_to.html#header-dep-change...