revert r354935 and apply fix for cleandir failure

This reapplies the RISC-V GNU ld workaround from r354896, r354899, and
354900, along with a fix for the build failure during cleandir.

LINKER_TYPE was not being set during cleandir, resulting in
Malformed conditional (${LINKER_TYPE} == "bfd" && ${MACHINE} == "riscv")
from Cirrus-CI.

PR: 242109
Sponsored by: The FreeBSD Foundation