In addition, start ordering header file includes to be in more
consistent order: system header files, src/utils, src/*, same
directory as the *.c file.
It looks like GnuTLS does not know how to parse the previously used
DER-formatted PKCS#1 private key (server.key). To work around this, use
a PEM-formatted version of the same key. This format can now be used by
OpenSSL, GnuTLS, and the internal TLS implementation.