There’s really not enough information there for anyone to help you, Michel.
If you’re trying to use Gentoo and Gentoo doesn’t have support for ARM, it’s not likely to have support for RISC-V - unless you add it.
I’m not familiar with Poppler, but it looks like it’s part of the Fedora distribution and has been building and running regression tests for years. zathura-pdf-poppler | Package Info | Fedora RISC-V BeagleV is running those rv64g Linux binaries from years ago, just as expected.
cMake is present on the Fedora distribution that’s where most of the BeagleV action is happening. (Other distros are working on bringing up their own infrastructure; Fedora was just the first out of the gate.)
[root@fedora-starfive ~]# which cmake ; cmake --version ; head -5 /proc/cpuinfo
cmake version 3.18.4
CMake suite maintained and supported by Kitware (kitware.com/cmake).
processor : 0
hart : 1
isa : rv64imafdc
mmu : sv39
uarch : starfive,rocket0
As for ‘catch 22’, most environments solve this via cross development. It’s pretty well understood through the industry.
If you have questions that are specific to BeagleV, we can help but we need WAY more to work on than you’ve given us. Unless you’re actually DOING OS development starting with a supported OS is a pretty good foundation, for example.