Bugfix/fix redundant compiler flags (#658)

* Improved GCC compiler flags in ARM, OS, and test builds. Removed redundant flags, and made them consistent across various builds.

* Fixed redundant redeclaration of various functions detected by change in compiler flags.

* Fixed string truncation warning in bip-init detected by change in compiler flags.

* Fixed some set-but-not-used variables by creating dummy functions instead of using macros.

src/bacnet/create_object.h

@@ -84,11 +84,6 @@ BACNET_STACK_EXPORT
 int create_object_error_ack_encode(
     uint8_t *apdu, uint8_t invoke_id, BACNET_CREATE_OBJECT_DATA *data);
 
-BACNET_STACK_EXPORT
-int create_object_ack_encode(
-    uint8_t *apdu, uint8_t invoke_id,
-    BACNET_CREATE_OBJECT_DATA *data);
-
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */