Don't depend on srv.c in config.h, but add explicit checks. This is more
in line with other options that only make sense server-side, and also it
allows to test full config minus srv.c more easily.
Use a custom function that minimally parses the message an creates a reply
without the overhead of a full SSL context.
Also fix dependencies: needs DTLS_HELLO_VERIFY for the cookie types, and let's
also depend on SRV_C as is doesn't make sense on client.
Things that are not guaranteed by the standard but should be true of all
platforms of interest to us:
- 8-bit chars
- NULL pointers represented by all-bits-zero
- DTLS_HELLO_VERIFY no longer depends on SRV_C
- SSL_COOKIE_C no longer depends on DTLS_HELLO_VERIFY
Not that much work for us, and easier on users (esp. since it allows just
disabling SRV_C alone).
* mbedtls-1.3:
Update generated file
Update Changelog for deprecation config flags
Fix tests to work with DEPRECATED_REMOVED
Add POLARSSL_DEPRECATED_{WARNING,REMOVED}
Suppress clang warning we don't want
