py/nativeglue: Remove dependency on mp_fun_table in dyn-compiler mode.

mpy-cross uses MICROPY_DYNAMIC_COMPILER and MICROPY_EMIT_NATIVE but does
not actually need to execute native functions, and does not need
mp_fun_table.  This commit makes it so mp_fun_table and all its entries are
not built when MICROPY_DYNAMIC_COMPILER is enabled, significantly reducing
the size of the mpy-cross executable and allowing it to be built on more
machines/OS's.

py/emitnative.c

@@ -609,8 +609,11 @@ STATIC void emit_native_end_pass(emit_t *emit) {
             const_table_alloc += nqstr;
         }
         emit->const_table = m_new(mp_uint_t, const_table_alloc);
+        #if !MICROPY_DYNAMIC_COMPILER
         // Store mp_fun_table pointer just after qstrs
+        // (but in dynamic-compiler mode eliminate dependency on mp_fun_table)
         emit->const_table[nqstr] = (mp_uint_t)(uintptr_t)mp_fun_table;
+        #endif
 
         #if MICROPY_PERSISTENT_CODE_SAVE
         size_t qstr_link_alloc = emit->qstr_link_cur;

py/mpconfig.h

@@ -338,6 +338,7 @@
 #endif
 
 // Whether the compiler is dynamically configurable (ie at runtime)
+// This will disable the ability to execute native/viper code
 #ifndef MICROPY_DYNAMIC_COMPILER
 #define MICROPY_DYNAMIC_COMPILER (0)
 #endif

py/nativeglue.c

@@ -95,7 +95,7 @@ mp_obj_t mp_native_to_obj(mp_uint_t val, mp_uint_t type) {
 
 #endif
 
-#if MICROPY_EMIT_NATIVE
+#if MICROPY_EMIT_NATIVE && !MICROPY_DYNAMIC_COMPILER
 
 STATIC mp_obj_dict_t *mp_native_swap_globals(mp_obj_dict_t *new_globals) {
     if (new_globals == NULL) {