Newlib configuration

What’s the correct place in the riscv-tools package to change the Newlib configuration? For instance, the default riscv-tools build doesn’t support printf positional arguments. So let’s imagine I wanted to change that. I tried to change this line:

# riscv-tools/riscv-gnu-toolchain/riscv-newlib/libgloss/riscv/
ac_configure_args="${ac_configure_args} --enable-multilib"


ac_configure_args="${ac_configure_args} --enable-multilib --enable-newlib-io-pos-args"

I built the toolchain but I didn’t notice any difference. How do you change the RISC-V Newlib configuration defaults?

In riscv-tools/riscv-gnu-toolchain/, there is a stamps/build-newlib rule that specifies configure options for newlib. There is also a stamps/build-newlib-nano rule if you want the newlib nano library to have the same change.