Build with USE_LIBWRAP on Debian Forky fails

It gives the error 
```
CMake Error at src/CMakeLists.txt:129 (target_sources):
  Cannot find source file:

    wrap

  Tried extensions .c .C .c++ .cc .cpp .cxx .cu .mpp .m .M .mm .ixx .cppm
  .ccm .cxxm .c++m .h .hh .h++ .hm .hpp .hxx .in .txx .f .F .for .f77 .f90
  .f95 .f03 .hip .ispc
```

Note that commit 33d1439 does not fix this.