py/emitglue: Simplify mp_raw_code_t's kind and scope_flags members.
To simplify their access and reduce code size.
The `scope_flags` member is only ever used to determine if a function is a
generator or not, so make it reflect that fact as a bool type.
Signed-off-by: Damien George <damien@micropython.org>
diff --git a/py/runtime0.h b/py/runtime0.h
index 69af38d..9c6f0e0 100644
--- a/py/runtime0.h
+++ b/py/runtime0.h
@@ -26,8 +26,11 @@
#ifndef MICROPY_INCLUDED_PY_RUNTIME0_H
#define MICROPY_INCLUDED_PY_RUNTIME0_H
-// The first four must fit in 8 bits, see emitbc.c
-// The remaining must fit in 16 bits, see scope.h
+// These constants are used by:
+// - mp_raw_code_t::is_generator (only MP_SCOPE_FLAG_GENERATOR)
+// - scope_t::scope_flags (16 bits)
+// - MP_BC_PRELUDE_SIG_ENCODE macro, masked by MP_SCOPE_FLAG_ALL_SIG (4 bits)
+// - tools/mpy_ld.py, when generating mpy files (maximum 7 bits)
#define MP_SCOPE_FLAG_ALL_SIG (0x0f)
#define MP_SCOPE_FLAG_GENERATOR (0x01)
#define MP_SCOPE_FLAG_VARKEYWORDS (0x02)