Typedefs sha256_pin_t & getdns_log_config multiple declaration in context.h,
tls.h and tls_internal.h causes build error with some gnu99 compilers, even
if the redefinition is identical.
One possible way is to protect each occurence with ifdefs, but it seems too
brute, other one is to keep typedef in context.h only and use struct types
in recently added tls* scope.
Error example:
../libtool --quiet --tag=CC --mode=compile arm-brcm-linux-uclibcgnueabi-gcc
-std=gnu99 -I. -I. -I./util/auxiliary -I./tls -I./openssl -I./../stubby/src
-Wall -Wextra -D_BSD_SOURCE -D_DEFAULT_SOURCE ... -c ./convert.c -o convert.lo
In file included from ./context.h:53:0,
from ./util-internal.h:42,
from ./convert.c:50:
./tls.h:45:27: error: redefinition of typedef 'sha256_pin_t'
./openssl/tls-internal.h:57:27: note: previous declaration of 'sha256_pin_t' was here
In file included from ./util-internal.h:42:0,
from ./convert.c:50:
./context.h:133:3: error: redefinition of typedef 'sha256_pin_t'
./tls.h:45:27: note: previous declaration of 'sha256_pin_t' was here
./context.h:267:3: error: redefinition of typedef 'getdns_log_config'
./openssl/tls-internal.h:58:34: note: previous declaration of 'getdns_log_config' was here
Set the priority string to a concatenation of the connection cipher and curve strings, falling back to the context ones if the connection value isn't specified. Also get context.c to specify NULL for default context list and the opportunistic list for the connection, moving these library-specific quantities into the specific implementation.
Link to the openssl val_secalgo implementation and use that, after adjusting the source of Nettle includes.
GnuTLS uses Nettle itself, so this is not adding a new dependency.
Convert the main util/val_secalgo.h to a plain interface. Move the preprocessor redefines into validator/val_secalgo.h, and move THAT under openssl, because it is OpenSSL implementation specific at present - you can compile with NSS and Nettle if config allows.