fix some compiler warnings

demos/crypt.c

@@ -177,7 +177,8 @@ int main(int argc, char *argv[])
    }
 
    printf("\nEnter key: ");
-   fgets((char *)tmpkey,sizeof(tmpkey), stdin);
+   if(fgets((char *)tmpkey,sizeof(tmpkey), stdin) == NULL)
+      exit(-1);
    outlen = sizeof(key);
    if ((errno = hash_memory(hash_idx,tmpkey,strlen((char *)tmpkey),key,&outlen)) != CRYPT_OK) {
       printf("Error hashing key: %s\n", error_to_string(errno));

demos/hashsum.c

@@ -11,7 +11,7 @@
 
 int errno;
 
-void register_algs();
+void register_algs(void);
 
 int main(int argc, char **argv)
 {