(svn r25508) -Change: split unit localisation choice into a choice per type of unit, and move it to the advanced settings

-Feature [FS#5482]: have tractive effort in imperial (lbf) and metric (kgf) units
-Feature: have weights and volumes in imperial units (short tons, gallons)

src/saveload/oldloader_sl.cpp

@@ -1577,6 +1577,7 @@ extern uint16 _disaster_delay;
 extern byte _trees_tick_ctr;
 extern byte _age_cargo_skip_counter; // From misc_sl.cpp
 extern uint8 _old_diff_level;
+extern uint8 _old_units;
 static const OldChunks main_chunk[] = {
 	OCL_ASSERT( OC_TTD, 0 ),
 	OCL_ASSERT( OC_TTO, 0 ),
@@ -1705,7 +1706,7 @@ static const OldChunks main_chunk[] = {
 	OCL_NULL( 1 ),               ///< Station tick counter, no longer in use
 
 	OCL_VAR (  OC_UINT8,    1, &_settings_game.locale.currency ),
-	OCL_VAR (  OC_UINT8,    1, &_settings_game.locale.units ),
+	OCL_VAR (  OC_UINT8,    1, &_old_units ),
 	OCL_VAR ( OC_FILE_U8 | OC_VAR_U32,    1, &_cur_company_tick_index ),
 
 	OCL_NULL( 2 ),               ///< Date stuff, calculated automatically