Fix build errors on raspberry pi (#1454)

Author: functionpointer

hal/architecture/Linux/drivers/core/config.c

@@ -31,6 +31,8 @@ static int _config_create(const char *config_file);
 static int _config_parse_int(char *token, const char *name, int *value);
 static int _config_parse_string(char *token, const char *name, char **value);
 
+struct config conf;
+
 int config_parse(const char *config_file)
 {
 	FILE *fptr;

hal/architecture/Linux/drivers/core/config.h

@@ -39,7 +39,9 @@ struct config {
 	char *soft_hmac_key;
 	char *soft_serial_key;
 	char *aes_key;
-} conf;
+};
+
+extern struct config conf;
 
 int config_parse(const char *config_file);
 void config_cleanup(void);