This appears to be needed on FreeBSD:
ld.lld: error: undefined symbol: scalbnf
referenced by divsc3.c:26 (/Users/alex/cheri/cheribsd/contrib/llvm-project/compiler-rt/lib/builtins/divsc3.c:26)
divsc3.o:(__divsc3) in archive /Users/alex/cheri/output/sdk/sysroot-riscv64/usr/lib64/libgcc.areferenced by divsc3.c:27 (/Users/alex/cheri/cheribsd/contrib/llvm-project/compiler-rt/lib/builtins/divsc3.c:27)
divsc3.o:(__divsc3) in archive /Users/alex/cheri/output/sdk/sysroot-riscv64/usr/lib64/libgcc.areferenced by divsc3.c:31 (/Users/alex/cheri/cheribsd/contrib/llvm-project/compiler-rt/lib/builtins/divsc3.c:31)
divsc3.o:(__divsc3) in archive /Users/alex/cheri/output/sdk/sysroot-riscv64/usr/lib64/libgcc.areferenced 1 more times