force HAVE_HASHDRBG enabled in settings.h unless WOLFSSL_FORCE_RC4_DRBG flag set

wolfssl/wolfcrypt/random.h

@@ -35,6 +35,9 @@
 #endif
 
 #ifndef HAVE_FIPS /* avoid redefining structs and macros */
+#if defined(WOLFSSL_FORCE_RC4_DRBG) && defined(NO_RC4)
+    #error Cannot have WOLFSSL_FORCE_RC4_DRBG and NO_RC4 defined.
+#endif /* WOLFSSL_FORCE_RC4_DRBG && NO_RC4 */
 #if defined(HAVE_HASHDRBG) || defined(NO_RC4)
     #ifdef NO_SHA256
         #error "Hash DRBG requires SHA-256."

wolfssl/wolfcrypt/settings.h

@@ -790,6 +790,12 @@
     #define NO_OLD_TLS
 #endif
 
+/* If not forcing to use ARC4 as the DRBG, always enable Hash_DRBG */
+#undef HAVE_HASHDRBG
+#ifndef WOLFSSL_FORCE_RC4_DRBG
+    #define HAVE_HASHDRBG
+#endif
+
 /* Place any other flags or defines here */