[Rd] R-admin.html fixes (for cairo support in windoze)

[Hiroyuki Kawakatsu]

Hi,

For building r56651 on windoze (32bit), I was re-reading R-admin.html
and noticed cairo support (section 3.1.5). The description in that
section appears to be missing the instruction to build the dll. By
looking at the makefile, I figured that to be `make cairodevices'.

Also the links in option 1 appear to be dead. After downloading
several files, I found that the "bundled" file
http://ftp.gnome.org/pub/gnome/binaries/win32/gtk+/2.22/gtk+-bundle_2.22.1-20101227_win32.zip
seems the easiest to use (for option 1).

h.
-- 
+---
| Hiroyuki Kawakatsu
| Business School, Dublin City University
| Dublin 9, Ireland. Tel +353 (0)1 700 7496