NetBSD fixes

[0-wiz-0]

I've ported libindi to pkgsrc and needed these patches to fix the build on NetBSD. Please review and apply them.
Thanks.

[knro]

@0-wiz-0 Please check the errors in the build

[0-wiz-0]

I had a typo in the __linux__ macro, sorry for that.

There is however other fallout that looks unrelated:

Debian:

Run indi/scripts/indi-core-deb.sh
/__w/indi/indi/build/deb_indi-core /__w/indi/indi
make: dh_listpackages: No such file or directory
make: dh_listpackages: No such file or directory
make: Nothing to be done for 'binary'.
/__w/indi/indi/build/deb_indi-core
/__w/indi/indi

Available packages:
ls: cannot access 'build/*.deb': No such file or directory
Error: Process completed with exit code 2.

Fedora:

[  4%] Linking CXX executable fakedriver
/__w/indi/indi/indi/libs/dsp/stream.c: In function 'dsp_stream_new':
/__w/indi/indi/indi/libs/dsp/stream.c:132:19: error: allocation of insufficient size '0' for type 'dsp_t' {aka 'double'} with size '8' [-Werror=alloc-size]
  132 |     stream->buf = (dsp_t*)malloc(sizeof(dsp_t) * 0);
      |                   ^
/__w/indi/indi/indi/libs/dsp/stream.c:133:23: error: allocation of insufficient size '0' for type 'double' with size '8' [-Werror=alloc-size]
  133 |     stream->dft.buf = (double*)malloc(sizeof(dsp_t) * 0);
      |                       ^

[0-wiz-0]

Thank @knro you for merging this!