Fix linux bridges build

source/backend/engine/CarlaEngineBridge.cpp

@@ -907,8 +907,7 @@ CarlaEngine* CarlaEngine::newBridge(const char* const audioPoolBaseName, const c
 
 // -----------------------------------------------------------------------
 
-// TODO later
-#if defined(CARLA_OS_WIN)
+#ifdef BRIDGE_PLUGIN
 CarlaPlugin* CarlaPlugin::newNative(const CarlaPlugin::Initializer&)              { return nullptr; }
 CarlaPlugin* CarlaPlugin::newFileGIG(const CarlaPlugin::Initializer&, const bool) { return nullptr; }
 CarlaPlugin* CarlaPlugin::newFileSF2(const CarlaPlugin::Initializer&, const bool) { return nullptr; }

source/bridges-plugin/Makefile

@@ -8,7 +8,7 @@ include ../Makefile.mk
 
 # --------------------------------------------------------------
 
-BUILD_CXX_FLAGS += -DBUILD_BRIDGE
+BUILD_CXX_FLAGS += -DBUILD_BRIDGE -DBRIDGE_PLUGIN
 BUILD_CXX_FLAGS += -I. -I../backend -I../includes -I../utils -isystem ../modules
 BUILD_CXX_FLAGS += $(LIBLO_FLAGS)
 LINK_FLAGS      += $(LIBLO_LIBS)