diff --git a/Makefile b/Makefile
index cf2da96e7..556aeb10f 100644
--- a/Makefile
+++ b/Makefile
@@ -139,7 +139,7 @@ endif
 CFLAGS += $(shell $(PKGCONFIG) --cflags ${PKGS})
 LDLIBS += $(shell $(PKGCONFIG) --libs ${PKGS})
 
-all: src plugins tools
+all: src plugins tools tests clients
 src plugins tools tests: lib
 
 # Build all variants: debug, coverage, ...
diff --git a/clients/Makefile.inc b/clients/Makefile.inc
index 354abeaf5..162850c03 100644
--- a/clients/Makefile.inc
+++ b/clients/Makefile.inc
@@ -20,23 +20,15 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ###################################################################################
 
-ASYNCIP_PATH = $(SRCDIR)/clients/opal/models/send_receive
+CLIENTS =
+	
+ifneq ($(wildcard $(SRCDIR)/thirdparty/libopal/include/opal/AsyncApi.h),)
+	-include $(SRCDIR)/clients/Makefile.opal.inc
+endif
 
-ASYNCIP_OPTS = RTLAB_INTEL_COMPILER=0 \
-		PROTOCOL=GTNET_SKT \
-		OPAL_LIBS="-lSystem -luuid" \
-		OPAL_LIBPATH=-L$(SRCDIR)/thirdparty/libopal/ \
-		OPAL_INCPATH=-I$(SRCDIR)/thirdparty/libopal/include/opal
+clients: $(addprefix clients-,$(CLIENTS))
 
-clients: clients-opal
-
-clients-opal:
-	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk AsyncIP $(ASYNCIP_OPTS)
-
-clean-clients:
-	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk clean $(ASYNCIP_OPTS)
-
-install-clients:
-	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk install $(ASYNCIP_OPTS)
+clean-clients: $(addprefix clean-clients-,$(CLIENTS))
+install-clients: $(addprefix install-clients-,$(CLIENTS))
 
 .PHONY: clients clean-clients install-clients
diff --git a/clients/Makefile.opal.inc b/clients/Makefile.opal.inc
new file mode 100644
index 000000000..c67bede93
--- /dev/null
+++ b/clients/Makefile.opal.inc
@@ -0,0 +1,42 @@
+# Makefile.
+#
+# @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+# @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
+# @license GNU General Public License (version 3)
+#
+# VILLASnode
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+###################################################################################
+
+CLIENTS += opal
+
+ASYNCIP_PATH = $(SRCDIR)/clients/opal/models/send_receive
+
+ASYNCIP_OPTS = RTLAB_INTEL_COMPILER=0 \
+		PROTOCOL=GTNET_SKT \
+		OPAL_LIBS="-lSystem -luuid" \
+		OPAL_LIBPATH=-L$(SRCDIR)/thirdparty/libopal/ \
+		OPAL_INCPATH=-I$(SRCDIR)/thirdparty/libopal/include/opal
+		
+clients-opal:
+	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk AsyncIP $(ASYNCIP_OPTS)
+		
+clean-clients-opal:
+	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk clean $(ASYNCIP_OPTS)
+
+install-clients-opal:
+	$(MAKE) -C $(ASYNCIP_PATH) -f Makefile.mk install $(ASYNCIP_OPTS)
+
+.PHONY: clients-opal clean-clients-opal install-clients-opal
diff --git a/lib/nodes/Makefile.inc b/lib/nodes/Makefile.inc
index e173fecb3..0ddb86bb2 100644
--- a/lib/nodes/Makefile.inc
+++ b/lib/nodes/Makefile.inc
@@ -101,11 +101,11 @@ endif
 
 # Enable OPAL-RT Asynchronous Process support (will result in 32bit binary!!!)
 ifeq ($(WITH_OPAL),1)
-ifneq ($(wildcard thirdparty/libopal/include/opal/AsyncApi.h),)
+ifneq ($(wildcard $(SRCDIR)/thirdparty/libopal/include/opal/AsyncApi.h),)
 	LIB_OBJS    += opal.o
 
-	LIB_CFLAGS  += -I thirdparty/libopal/include/opal/ -DWITH_OPAL
-	LIB_LDFLAGS += -L/lib/i386-linux-gnu/ -L/usr/lib/i386-linux-gnu/ -Lthirdparty/libopal/
+	LIB_CFLAGS  += -I $(SRCDIR)/thirdparty/libopal/include/opal/ -DWITH_OPAL
+	LIB_LDFLAGS += -L/lib/i386-linux-gnu/ -L/usr/lib/i386-linux-gnu/ -L$(SRCDIR)/thirdparty/libopal/
 	LIB_LDLIBS  += -lOpalAsyncApiCore -lOpalCore -lOpalUtils -lirc
 
 	# libOpalAsyncApi is a 32bit library. So we need to build everything in 32bit