disable ltc_rng by default

src/misc/crypt/crypt.c

@@ -371,6 +371,9 @@ const char *crypt_build_settings =
 #if defined(LTC_RNG_MAKE_PRNG)
     " LTC_RNG_MAKE_PRNG "
 #endif
+#if defined(LTC_PRNG_ENABLE_LTC_RNG)
+    " LTC_PRNG_ENABLE_LTC_RNG "
+#endif
 #if defined(LTC_HASH_HELPERS)
     " LTC_HASH_HELPERS "
 #endif

src/misc/crypt/crypt_prng_rng_descriptor.c

@@ -10,4 +10,6 @@
  */
 #include "tomcrypt.h"
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
 unsigned long (*ltc_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
+#endif