One last note that should have been included in my first reply:
Before trying to build GIMP, install at least the following.
sudo apt-get install fontconfig gtk-doc-tools intltool libcairo2
libdbus-glib-1-2 libexif-dev libfontconfig1 libfreetype6 libgdk-pixbuf2.0-0
libgtk-3-0 libjasper-dev libjpeg62-dev liblcms1-dev liblcms-dev libmng-dev
libopenexr-dev libpango1.0-0 libpng-dev libpoppler-dev librsvg2-common
librsvg2-dev libtiff4-dev libtiff-tools libtool libwebkit-dev libwmf-dev
pkg-config python-dev python-gtk2-dev ruby libgirepository1.0-dev
gobject-introspection
