gnuradio-3.8 build fails with error: cannot convert const string {aka const std::__cxx11::basic_string} to pmt::pmt_t {aka boost::shared_ptr}

[Tom Crane]

I am attempting to build the v.3.8 source under Slackware64 Linux and 
can't get past this and a few subsequent errors.

Building from the git source results in the same failure.
Build system details:
 o gcc 9.2.0
 o SWIG version 4.0.1
 o Boost 1.72.0

My build scripts and build logs are here 
https://www.mklab.rhul.ac.uk/~tom/tvdx/gr/build_problems/

Please advise.

Many thanks
Tom Crane

--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email:  t.cr...@rhul.ac.uk
Fax:    +44 (0) 1784 472794