unix, stmhal: Add option for STR_UNICODE to mpconfigport.h.
Unicode is disabled by default for now, since FileIO.read(n) is
currently not implemented for text-mode files, and this is an
often function.
diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index 1559bdb..763b34b 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -41,6 +41,7 @@
#define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_MPZ)
#define MICROPY_STREAMS_NON_BLOCK (1)
#define MICROPY_OPT_COMPUTED_GOTO (1)
+#define MICROPY_PY_BUILTINS_STR_UNICODE (0)
#define MICROPY_PY_BUILTINS_FROZENSET (1)
#define MICROPY_PY_SYS_EXIT (1)
#define MICROPY_PY_SYS_PLATFORM "linux"