message: Add compiler flags to reduce binary size.
diff: @@ -18,6 +18,8 @@ ifeq ($(TARGET), xtensa-xpg)
  -DXTENSA -DMAX_RFFT_PWR=9 -DMIN_RFFT_PWR=MAX_RFFT_PWR \
  -fdata-sections \
  -ffunction-sections \
  + -fno-exceptions \
  + -fno-unwind-tables \
  -fmessage-length=0
  TARGET_TOOLCHAIN_PREFIX := xt-
  