refactor: the default dowcasting mode changed from AUTO to ON

src/CMakeLists.txt

@@ -27,7 +27,7 @@ project(mp-units
     LANGUAGES CXX
 )
 
-set(DOWNCAST_MODE AUTO CACHE STRING "Select downcasting mode")
+set(DOWNCAST_MODE ON CACHE STRING "Select downcasting mode")
 set_property(CACHE DOWNCAST_MODE PROPERTY STRINGS AUTO ON OFF)
 
 # set path to custom cmake modules

src/include/units/bits/external/downcasting.h

@@ -30,7 +30,7 @@
 #error "Invalid DOWNCAST_MODE value"
 #endif
 #else
-#define DOWNCAST_MODE 2
+#define DOWNCAST_MODE 1
 #endif
 
 namespace units {