Deprecate the recursive includes of bn.h from various API headers (asn1.h,

dh.h, dsa.h, ec.h, ecdh.h, ecdsa.h, rsa.h), as the opaque bignum types are
already declared in ossl_typ.h. Add explicit includes for bn.h in those C
files that need access to structure internals or API functions+macros.

crypto/ec/ectest.c

@@ -93,6 +93,7 @@ int main(int argc, char * argv[]) { puts("Elliptic curves are disabled."); retur
 #include <openssl/obj_mac.h>
 #include <openssl/objects.h>
 #include <openssl/rand.h>
+#include <openssl/bn.h>
 
 #define ABORT do { \
 	fflush(stdout); \