Add BUILD_TYPE macro to build_riscv.sh (#12167)

build_tools/cmake/build_riscv.sh

diff --git a/build_tools/cmake/build_riscv.sh b/build_tools/cmake/build_riscv.sh
index 042932f..d3f4978 100755
--- a/build_tools/cmake/build_riscv.sh
+++ b/build_tools/cmake/build_riscv.sh
@@ -22,6 +22,7 @@
 set -xeuo pipefail
 
 BUILD_DIR="${1:-${IREE_TARGET_BUILD_DIR:-build-riscv}}"
+BUILD_TYPE="${IREE_BUILD_TYPE:-RelWithDebInfo}"
 RISCV_PLATFORM="${IREE_TARGET_PLATFORM:-linux}"
 RISCV_ARCH="${IREE_TARGET_ARCH:-riscv_64}"
 RISCV_COMPILER_FLAGS="${RISCV_COMPILER_FLAGS:--O3}"
@@ -38,6 +39,7 @@
 args=(
   "-G" "Ninja"
   "-B" "${BUILD_DIR}"
+  "-DCMAKE_BUILD_TYPE=${BUILD_TYPE}"
   "-DPython3_EXECUTABLE=${IREE_PYTHON3_EXECUTABLE}"
   "-DPYTHON_EXECUTABLE=${IREE_PYTHON3_EXECUTABLE}"
   "-DCMAKE_TOOLCHAIN_FILE=${TOOLCHAIN_FILE}"