1. Make sure to install the mozilla build environment for your platform: windows, Mac OS X, linux. You will also need to install subversion. BlueGriffon is based on mozilla-central.
  2. create a new directory for BlueGriffon's and XULrunner's sources
  3. get mozilla-central from Mozilla through Mercurial
    hg clone http://hg.mozilla.org/mozilla-central mozilla-2.0
  4. get BlueGriffon's tree through subversion:
    cd mozilla-2.0
    svn checkout http://sources.disruptive-innovations.com/bluegriffon/trunk bluegriffon
  5. get BlueGriffon locales through subversion:
    cd bluegriffon
    svn checkout http://sources.disruptive-innovations.com/bluegriffon-l10n/trunk locales
  6. tweak variable  _AVAILABLE_LOCALES in file bluegriffon/langpacks/Makefile.in according to your wishes ; en-US is always built, this is for the extra locales
  7. use the right revision of Gecko and apply the patch to the trunk
    cd mozilla-2.0
    hg update -r `cat bluegriffon/config/mozilla_central_revision.txt`
    patch -p 1 < bluegriffon/config/content.patch
  8. create a .mozconfig file.The  settings I am using on a daily basis on OS X (Yosemite) can be found in bluegriffon/config/mozconfig.macosx .
  9. type make -f client.mk build_all
  10. bluegriffon.exe is in $MOZ_OBJDIR/dist/bin on windows/linux and BlueGriffon.app is in $MOZ_OBJDIR/dist on Mac (launch with open BlueGriffon.app)