In the early days, Greg modified buildroot to build a GNU toolchain specifically for NuttX (include files included). I wanted a toolchain that used the hard-float ABI for Armv7E-M. I maintained it (unofficially) for some time submitting patches (up to gcc 8.3, gdb 7.5 IIRC). I’m not sure what happened the the buildroot tree after Apache adoption.
It hasn't moved: https://bitbucket.org/nuttx/buildroot/src/master/ . But neither has it been maintained since your last changes.
Some words about the tool chain: * It builds a NuttX aware toolchain. For ARM, this is an arm-nuttx-eabi toolchain. * It does not link link with the newlib as do most OS ignorant toolchains. It links with the NuttX libc for guaranteed compatibility * It does not use the newlib header files; it uses the NuttX header files. * It predefines the __NuttX__ symbol
