-RISCV_PREFIX=riscv64-unknown-elf-
-RISCV_GCC = $(RISCV_PREFIX)gcc
-RISCV_GCC_OPTS = -static -std=gnu99 -O2 -ffast-math -fno-common -fno-builtin-printf
-RISCV_LINK = $(RISCV_GCC) -T $(bmarkdir)/common/test.ld $(incs)
-RISCV_LINK_MT = $(RISCV_GCC) -T $(bmarkdir)/common/test-mt.ld
-RISCV_LINK_OPTS = -nostdlib -nostartfiles -ffast-math -lc -lgcc
-RISCV_OBJDUMP = $(RISCV_PREFIX)objdump --disassemble-all --disassemble-zeroes --section=.text --section=.text.startup --section=.data
-RISCV_SIM = spike
+RISCV_PREFIX ?= riscv64-unknown-elf-
+RISCV_GCC ?= $(RISCV_PREFIX)gcc
+RISCV_GCC_OPTS ?= -static -std=gnu99 -O2 -ffast-math -fno-common -fno-builtin-printf
+RISCV_LINK ?= $(RISCV_GCC) -T $(src_dir)/common/test.ld $(incs)
+RISCV_LINK_MT ?= $(RISCV_GCC) -T $(src_dir)/common/test-mt.ld
+RISCV_LINK_OPTS ?= -nostdlib -nostartfiles -ffast-math -lc -lgcc
+RISCV_OBJDUMP ?= $(RISCV_PREFIX)objdump --disassemble-all --disassemble-zeroes --section=.text --section=.text.startup --section=.data
+RISCV_SIM ?= spike