Module install Error: Unable to find 'pmt_swig.i'

using the usual method, i am trying to install the 4fsk demodulator
block and i get this error:

make[2]: Entering directory `/home/matt/gr-fsk4/src/lib’
/usr/bin/swig -c++ -fvirtual -python -modern
-I/usr/local/include/gnuradio/swig -I/usr/local/include/gnuradio -module
fsk4 -o …/…/src/lib/fsk4.i
/usr/local/include/gnuradio/swig/gr_basic_block.i:26: Error: Unable to
find ‘pmt_swig.i’

the pmt_swig.i file is one of the directories here (usr/
local/include/gruel/swig) and note that when i execute op25 (another
decoder block which uses the fsk4) the first output line is “Imported
legacy fsk4”. so now i am confused as to how grc is importing the fsk4
if i cant even install it?

Thanks guys,