Revert "Revert "Missed some things in prev commit.""

This reverts commit 2e59788aa9.

SConstruct

@@ -308,6 +308,8 @@ if selected_platform in platform_list:
 	if (env['colored']=='yes'):
 		methods.colored(sys,env)
 		
+	if (env['etc1']=='yes'):
+		env.Append(CPPFLAGS=['-DETC1_ENABLED'])
 
 	Export('env')
 

drivers/etc1/SCsub

@@ -6,7 +6,8 @@ etc_sources = [
 	"etc1/rg_etc1.cpp"
 ]
 
-env.drivers_sources+=etc_sources
+if (env["etc1"] != "no"):
+    env.drivers_sources+=etc_sources
 
 #env.add_source_files(env.drivers_sources, etc_sources)
 

drivers/register_driver_types.cpp

@@ -222,7 +222,10 @@ void register_driver_types() {
 #endif
 #endif
 
+#ifdef ETC1_ENABLED
 	_register_etc1_compress_func();
+#endif
+
 	initialize_chibi();
 }