Compile fails on macOS X 10.12 with clang

[michaeljclark]

In file included from ../fesvr/tsi.cc:1:
../fesvr/tsi.h:39:10: warning: 'chunk_align' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
  size_t chunk_align() { return 4; }
         ^
../fesvr/htif.h:35:18: note: overridden virtual function is here
  virtual size_t chunk_align() = 0;
                 ^
In file included from ../fesvr/tsi.cc:1:
../fesvr/tsi.h:40:10: warning: 'chunk_max_size' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
  size_t chunk_max_size() { return 1024; }
         ^
../fesvr/htif.h:36:18: note: overridden virtual function is here
  virtual size_t chunk_max_size() = 0;
                 ^
../fesvr/tsi.cc:34:7: error: use of undeclared identifier 'abort'
      abort();
      ^
2 warnings and 1 error generated.
make: *** [tsi.o] Error 1

[michaeljclark]

fesvr-mac.patch.txt