Error building ion Daemon on macOS (Issue reported in Discord)

[IONOMY-Batman]

I have problems building the ion daemon on macos. I did this instruction https://github.com/ioncoincore/ion/blob/master/doc/build-osx.md and the generic build https://github.com/ioncoincore/ion/blob/master/doc/build-generic.md but when I am cd'ed into the 'depends' folder, and do 'make -j4' I get an error:

./google/protobuf/stubs/common.h:38:10: fatal error: 'assert.h' file not found
#include <assert.h>
         ^~~~~~~~~~
In file included from google/protobuf/stubs/atomicops_internals_x86_msvc.cc:37:
In file included from ./google/protobuf/stubs/atomicops.h:59:
In file included from ./google/protobuf/stubs/platform_macros.h:34:
./google/protobuf/stubs/common.h:38:10: fatal error: 'assert.h' file not found
#include <assert.h>
         ^~~~~~~~~~
In file included from google/protobuf/stubs/atomicops_internals_x86_gcc.cc:34:
In file included from /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/cstring:60:
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/string.h:60:15: fatal error: 
      'string.h' file not found
#include_next <string.h>
              ^~~~~~~~~~
1 error generated.
1 error generated.
make[1]: *** [google/protobuf/stubs/atomicops_internals_x86_msvc.lo] Error 1
make[1]: *** Waiting for unfinished jobs....
make[1]: *** [google/protobuf/stubs/atomicops_internals_x86_gcc.lo] Error 1
1 error generated.
make[1]: *** [google/protobuf/compiler/main.o] Error 1
1 error generated.
make[1]: *** [google/protobuf/stubs/common.lo] Error 1
make: *** [/Users/(user)/projects/ion/depends/work/build/x86_64-apple-darwin19.6.0/native_protobuf/2.6.1-706f05bcc9c/./.stamp_built] Error 2```