Worked on the nxp-upstream/zephyr repository to address a critical build stability issue related to header inclusion in embedded systems development. Focused on C programming and RTOS environments, the developer resolved a bug where macros in Cortex-M headers were not reliably defined before use in assembly contexts. By adjusting the include order of arm-m-switch.h within exception.h and extending the _ASMLANGUAGE guard to cover macro definitions, the changes ensured consistent macro availability and prevented build-time failures across toolchains. This work improved header reliability, reduced CI failures, and established safer integration patterns for assembly and C code in embedded RTOS projects.