Getting XI2.1 on your machine - http://xqms.github.com/blog/getting_xi21.html

build.sh

jhbuild -f jhbuildrc buildone inputproto xserver libXi xf86-input-evdev

config_git.sh

cd <module_dir>
git remote add whot <git url>
git checkout whot/<branch>

gcc_error.log

make[5]: Betrete Verzeichnis '/home/max/devel/privat/pscroll/xorg/xserver/hw/xfree86/common'
  CC     xf86Configure.lo
In file included from xf86Config.h:36:0,
                 from xf86Configure.c:31:
./../parser/xf86Optrec.h:94:32: error: redefinition of typedef ‘XF86OptionPtr’
xf86Opt.h:72:32: note: previous declaration of ‘XF86OptionPtr’ was here
In file included from ../../../hw/xfree86/os-support/xf86_OSlib.h:408:0,
                 from xf86Configure.c:32:
../../../hw/xfree86/os-support/xf86_OSproc.h:132:32: error: redefinition of typedef ‘XF86OptionPtr’
./../parser/xf86Optrec.h:94:32: note: previous declaration of ‘XF86OptionPtr’ was here
make[5]: *** [xf86Configure.lo] Fehler 1

jhbuildrc

checkoutroot = '/home/max/devel/privat/pscroll'

moduleset = os.path.join(checkoutroot, 'xorg/util/modular/xorg.modules')

modules = [ 'xorg' ]

# All modules will be in ROOT_DIR/ after the checkout
prefix = os.path.join(checkoutroot, 'build')
os.environ['ACLOCAL'] = 'aclocal -I ' + os.path.join(prefix, 'share', 'aclocal')
os.environ['PKG_CONFIG_PATH'] = os.path.join(prefix, 'lib', 'pkgconfig') \
    + ':' + os.path.join(prefix, 'share', 'pkgconfig')

branches = {
        'xserver': ('git://people.freedesktop.org/~whot/xserver', 'next-all'),
        'inputproto': ('git://people.freedesktop.org/~whot/inputproto', 'smooth-scrolling'),
        'libXi': ('git://people.freedesktop.org/~whot/libXi', 'smooth-scrolling'),
        'xf86-input-evdev': ('git://people.freedesktop.org/~whot/xf86-input-evdev', 'smooth-scrolling'),
}