Update Android port

Update Android port

* configure.ac: Check for madvise.
* lisp/international/fontset.el (script-representative-chars):
Improve detection of CJK fonts.
* src/pdumper.c (dump_discard_mem): Use madvise if possible.
* src/sfnt.c (sfnt_map_glyf_table, sfnt_unmap_glyf_table): New
functions.
* src/sfnt.h (struct sfnt_glyf_table): New field.
* src/sfntfont.c (struct sfnt_font_info, sfntfont_open)
(sfntfont_close, sfntfont_detect_sigbus): Allow mmapping fonts
if possible.
* src/sfntfont.h: Update prototypes.
* src/sysdep.c (handle_sigbus, init_sigbus, init_signals):
Initialize SIGBUS correctly.