Bill,
Type changes were required in several places in the files tbls.h, tbls.cc, aux_sub.h and aux_sub.cc. With these in place I can now successfully compile and run op25 on Raspbian Stretch using gcc-6.3.0 without using the -Wno-narrowing hack.
You can either clone my repo from https://github.com/boatbod/op25.git or pull just the changed files. https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/... https://raw.githubusercontent.com/boatbod/op25/master/op25/gr-op25_repeater/...
Graham