extmod: Move fsusermount.c from stmhal for cross-port reuse.
diff --git a/py/builtin.h b/py/builtin.h
index 891b93e..5653c48 100644
--- a/py/builtin.h
+++ b/py/builtin.h
@@ -105,4 +105,7 @@
extern const mp_obj_module_t mp_module_machine;
extern const mp_obj_module_t mp_module_lwip;
+// extmod functions
+MP_DECLARE_CONST_FUN_OBJ(pyb_mount_obj);
+
#endif // __MICROPY_INCLUDED_PY_BUILTIN_H__
diff --git a/py/py.mk b/py/py.mk
index 00a8c59..75e7f46 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -167,6 +167,7 @@
../extmod/modubinascii.o \
../extmod/modmachine.o \
../extmod/modussl.o \
+ ../extmod/fsusermount.o \
# prepend the build destination prefix to the py object files
PY_O = $(addprefix $(PY_BUILD)/, $(PY_O_BASENAME))