Update Android port

Update Android port

* src/androidterm.c (struct android_get_extracted_text_context):
New field `mark_active'.
(android_get_extracted_text): Set that field.
(struct android_extracted_text_class): New field `flags'.
(android_build_extracted_text): New argument `mark_active'.  Set
flags appropriately.
(NATIVE_NAME, android_update_selection): Likewise.
* src/textconv.c (get_extracted_text): New argument
`mark_active'.  Set it if the mark is active.
* src/textconv.h: Update prototypes.