- flag -I\$(abs_top_builddir)/include needs to be in both SWIG_SWIGFLAGS
  and SWIG_CPPFLAGS, for interface preprocessing/generation and compilation
- remove extraneous -I\$(top_builddir)/include from end of SWIG_CPPFLAGS
Original: 3d5852184dce91962be1343a83c992f18d0e6f47