Very very rudimentary support for -target:linux_arm64 -subtarget:android

src/checker.cpp

@@ -1149,6 +1149,7 @@ gb_internal void init_universal(void) {
 		GlobalEnumValue values[Subtarget_COUNT] = {
 			{"Default", Subtarget_Default},
 			{"iOS",     Subtarget_iOS},
+			{"Android", Subtarget_Android},
 		};
 
 		auto fields = add_global_enum_type(str_lit("Odin_Platform_Subtarget_Type"), values, gb_count_of(values));