Firmware build fails with GCC 15.2

[martinling]

Using Arm GNU toolchain 15.2.Rel1 (Build arm-15.86), I get the following linker errors (paths trimmed):

arm-none-eabi-ld: libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.S.obj(_lock_mutex):
  Unknown destination type (ARM/Thumb) in libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.c.obj
libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.c.obj: in function `libgreat_mutex_lock':
libgreat/firmware/platform/lpc43xx/sync.c:29:(.text.libgreat_mutex_lock+0x8): dangerous relocation: unsupported relocation
arm-none-eabi-ld: libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.S.obj(_unlock_mutex):
  Unknown destination type (ARM/Thumb) in libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.c.obj
libgreat/CMakeFiles/libgreat.dir/platform/lpc43xx/sync.c.obj: in function `libgreat_mutex_unlock':
libgreat/firmware/platform/lpc43xx/sync.c:38:(.text.libgreat_mutex_unlock+0x8): dangerous relocation: unsupported relocation
collect2: error: ld returned 1 exit status