add a symlink so that we can still include like freetype/freetype.h.
m4 is required to build libsigc++.
version up : ImageMagick 6.8.8-2 with lcms2 support.
use our own gettext in building inkscape.
add possibly missing LDFLAGS and LD_LIBRARY_PATH.

they seem not required in Ubuntu 13.10 but required in openSUSE 12.1.