This is on HPE NonStop x86
The OSSL_TIME definition is not available in a post-install OpenSSL instance. It appears that this only works when referencing a built instance from source. Is that the intent?
Also, on some platforms, uint64_t is not defined by the compiler but needs stdint.h.
Also, having some other options, like CPPFLAGS is not inheriting from the command line, -pthread is a non-portable option.