That's out of date, libgccjit exists. LLVM is a bit difficult to use as a library because it has no stable API and is in C++ so it doesn't have a stable ABI either.
Hmm.. why is it called "jit"? That seems like it's telling everyone the use case is very different from LLVM. Also the big EXPERIMENTAL banner doesn't instill confidence. Unlike with LLVM which is used by dozens of production languages.