CMake Error with RISCV32GCC_DIR

What should be the value of the RISCV32GCC_DIR env var? (I tried installing the VM but could not, so I am following the steps from https://open-isa.org/get-started/ directly).

Commands:

cd rv32m1_sdk_riscv/boards/rv32m1_vega/demo_apps/hello_world/ri5cy/riscvgcc
./build_debug.sh

Result:

CMake Error at /home/martin/riscv/rv32m1_sdk_riscv/tools/cmake_toolchain_files/riscv32gcc.cmake:23 (MESSAGE):
  ***Please set RISCV32GCC_DIR in envionment variables***
Call Stack (most recent call first):
  /usr/share/cmake-3.10/Modules/CMakeDetermineSystem.cmake:91 (include)
  CMakeLists.txt

CMake Error: CMake was unable to find a build program corresponding to "Unix Makefiles".  CMAKE_MAKE_PROGRAM is not set.  You probably need to select a different build tool.
CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!
make: *** No targets specified and no makefile found.  Stop.