Install libjack on linux systems; Fix missing macro

Makefile

@@ -387,6 +387,8 @@ clean:
 	$(MAKE) clean -C source/bridges-plugin
 	$(MAKE) clean -C source/bridges-ui
 	$(MAKE) clean -C source/discovery
+	$(MAKE) clean -C source/interposer
+	$(MAKE) clean -C source/libjack
 	$(MAKE) clean -C source/modules
 	$(MAKE) clean -C source/native-plugins
 	$(MAKE) clean -C source/plugin
@@ -419,7 +421,7 @@ stoat:
 install:
 	# Create directories
 	install -d $(DESTDIR)$(BINDIR)
-	install -d $(DESTDIR)$(LIBDIR)/carla
+	install -d $(DESTDIR)$(LIBDIR)/carla/jack
 	install -d $(DESTDIR)$(LIBDIR)/pkgconfig
 	install -d $(DESTDIR)$(LIBDIR)/python3/dist-packages
 	install -d $(DESTDIR)$(DATADIR)/carla
@@ -476,6 +478,13 @@ endif
 		bin/carla-discovery-* \
 		$(DESTDIR)$(LIBDIR)/carla
 
+ifeq ($(LINUX),true)
+	# Install libjack
+	install -m 755 \
+		bin/jack/libjack.so.0 \
+		$(DESTDIR)$(LIBDIR)/carla/jack
+endif
+
 	# Install pkg-config files
 	install -m 644 \
 		data/*.pc \

source/libjack/Makefile

@@ -21,7 +21,7 @@ endif
 
 # ----------------------------------------------------------------------------------------------------------------------
 
-BUILD_CXX_FLAGS += -I$(CWD) -I$(CWD)/backend -I$(CWD)/includes -I$(CWD)/modules -I$(CWD)/utils -DBUILD_BRIDGE
+BUILD_CXX_FLAGS += -I$(CWD) -I$(CWD)/backend -I$(CWD)/includes -I$(CWD)/modules -I$(CWD)/utils
 LINK_FLAGS      += $(MODULEDIR)/juce_core.a
 LINK_FLAGS      += $(JUCE_CORE_LIBS)
 

source/libjack/libjack.hpp

@@ -18,6 +18,9 @@
 // need to include this first
 #include "CarlaDefines.h"
 
+// now define as bridge
+#define BUILD_BRIDGE 1
+
 // now include a bunch of stuff
 #include "CarlaBackendUtils.hpp"
 #include "CarlaBridgeUtils.hpp"
@@ -47,9 +50,6 @@
 #ifdef JACKBRIDGE_DIRECT
 # error "Cannot create custom jack server while linking to libjack directly"
 #endif
-#ifndef BUILD_BRIDGE
-# error "BUILD_BRIDGE not enabled, why?"
-#endif
 
 CARLA_BACKEND_START_NAMESPACE