Add gpgme build input for sup
sup: separate dependencies

create separate expressions for gems requiring native extensions to be
built:

* gpgme
* ncursesw_sup
* xapian_full_alaveteli
Rename ruby gpgme gem to ruby-gpgme
gnupg: use libiconvOrEmpty instead of libiconv (not required for glibc platforms)
sup: use libiconvOrEmpty instead of plain old libiconv
ghostscript: add libiconvOrEmpty to build inputs
Merge pull request #615 from lovek323/ghostscript

ghostscript: add libiconvOrEmpty to build inputs
Merge pull request #613 from errge/hflags

Add hflags
atk: add libintlOrEmpty as build input
Merge pull request #610 from lovek323/sup

Add sup expression
gdk-pixbuf: add libintlOrEmpty to build inputs
cairo: add correct include path for pixman.h
libgcrypt: attempt to fix i686-freebsd builds, #616

It would probably be better to get newer "as" from somewhere, but I
don't see how.
gtk2: fix compilation on darwin

* add libintlOrEmpty to build inputs
* allow cups to be disabled by setting config.gtk2.cups to false
pango: add correct cairo include path
firefox-21: make "use system cairo" optional, defaulting to false
haskell-haddock: add version 2.13.2.1
haskell-concurrent-extra: update to version 0.7.0.6
haskell-hakyll: update to version 4.3.0.0
qt48: hopefully a good fix for parallel builds, finally

It caused rare failures, mainly for Qt for creator build.