The idle_thread() cannot perform any stack manipulations since it
runs in the idle thread TCB context. Declare the function with
the naked attribute, to ensure that the compiler always eliminates
the function prologue. Previously we rely on the -O2 optimization
flag for this, which on certain compilers (clang for instance) may
not guarantee that the function prologue gets eliminated.
Signed-off-by: Chang Liu <chang_liu3@brown.edu>
604c7c106e