I’m the self-appointed maintainer of darktable on Solaris, which is a fairly easy gig to keep on top of. Here’s why that is so: darktable’s codebase is very portable. It’s not riddled with operating system-specific assumptions; it uses standard C (with some C++), and apart from the OpenCL support every prerequisite library is buildable on Solaris with gcc or g++. I’d prefer to use Oracle Solaris Studio because that’s my work compiler, but there’s no great incentive for me to beat up on all the prerequisites to make them behave.