add possibility to export RSA public key in SubjectPublicKeyInfo format

src/headers/tomcrypt_pk.h

@@ -5,6 +5,9 @@ enum {
    PK_PRIVATE=1
 };
 
+/* Indicates standard output formats that can be read e.g. by OpenSSL or GnuTLS */
+#define PK_STD          0x1000
+
 int rand_prime(void *N, long len, prng_state *prng, int wprng);
 int rand_bn_bits(void *N, int bits, prng_state *prng, int wprng);
 int rand_bn_range(void *N, void *limit, prng_state *prng, int wprng);