ifneq ($(shell which riscv64-unknown-elf-gcc 2>/dev/null),)
TOOLCHAIN= riscv64-unknown-elf-
else
$(error "No RISC-V toolchain found. Can't find riscv32-unknown-elf-gcc or riscv64-unknown-elf-gcc found in your systems PATH variable. Please install a valid toolchain and make it accessible!")
$(call CATASTROPHIC_ERROR,Missing toolchain,No RISC-V toolchain found. Can't find riscv32-unknown-elf-gcc or riscv64-unknown-elf-gcc found in your systems PATH variable. Please install a valid toolchain and make it accessible!)