apps: avoid using POSIX IO macros and functions when built without them.
apps: avoid using POSIX IO macros and functions when built without them.

Fall back to stdio functions if not available.

Fixes a daily run-checker failure (no-posix-io)

Reviewed-by: Richard Levitte <5fb523282dd7956571c80524edc2dccfa0bd8234@openssl.org>
Reviewed-by: Tomas Mraz <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16073)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl