compile
how do you compile this if I want to use this folder in another project?
Hmmm, by design, you #include hss.h into your code, and link in hss_lib.a or hss_lib_thread.a into your project. Is this not working? What build environment are you using?
using visual studio
How do I compile this in order to get an executable that I can use?
I tried it with Visual Studio 2019; I created an empty console project, imported the source files, excluding demo.c (I used test_hss.c as my 'main' program, hence I included all the other test_*.c files as well); it turns out that I needed to turn off OpenSSL support (I didn't have a copy of openssl available for VS, so I just set USE_OPENSSL to 0 in sha256.h); I excluded hss_thread_pthread.c (didn't have Posix support either); there were a few sprintf calls in the test files that I switched to sprintf_s; there were a few "signedness mismatch" warnings I ignored; and finally, as VS didn't give me an easy way to call parameters, I modified test_hss.c to automatically run all tests. With all that, it worked fine for me.
What problem are you running into?
How would I compile in Linux terminal to create exe to be used in another project?