Autotools building has a target for packaging OSX.
For Synfig-core:
if MACOSX_PKG
package: all pkg-info/macosx/synfig-core.info
[ -d pkg_root ] && $(RMDIR) pkg_root || true
make install-strip prefix="`pwd`/pkg_root"
$(srcdir)/config/package pkg_root pkg-info/macosx/synfig-core.info -r $(srcdir)/pkg-info/macosx/core-resources
endif
For Synfig Studio:
package-osx: all pkg-info/macosx/synfig-studio.info
[ -d pkg_root ] && $(RMDIR) pkg_root || true
convert images/installer_logo_osx.png $(srcdir)/pkg-info/macosx/studio-resources/background.tif
make install prefix="`pwd`/pkg_root"
$(srcdir)/config/package pkg_root pkg-info/macosx/synfig-studio.info -r $(srcdir)/pkg-info/macosx/studio-resources
if MACOSX_PKG
package: package-osx
endif
Both use synfig-(core|studio)/config/package (virtually identical). Is it still in use/useful?