diff --git a/tests/CommonLibs/Makefile.am b/tests/CommonLibs/Makefile.am
index e6790e69..941badb9 100644
--- a/tests/CommonLibs/Makefile.am
+++ b/tests/CommonLibs/Makefile.am
@@ -1,6 +1,17 @@
 include $(top_srcdir)/Makefile.common
 
-AM_CPPFLAGS = -Wall -I$(top_srcdir)/CommonLibs $(STD_DEFINES_AND_INCLUDES) $(LIBOSMOCORE_CFLAGS) $(LIBOSMOCTRL_CFLAGS) $(LIBOSMOVTY_CFLAGS) -g
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/CommonLibs \
+	$(STD_DEFINES_AND_INCLUDES) \
+	$(NULL)
+
+AM_CXXFLAGS = \
+	-Wall -g \
+	$(LIBOSMOCORE_CFLAGS) \
+	$(LIBOSMOCTRL_CFLAGS) \
+	$(LIBOSMOVTY_CFLAGS) \
+	$(NULL)
+
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS) $(LIBOSMOCTRL_LIBS) $(LIBOSMOVTY_LIBS)
 
 EXTRA_DIST = BitVectorTest.ok \
diff --git a/tests/Transceiver52M/Makefile.am b/tests/Transceiver52M/Makefile.am
index 9fae41fb..cb22c2a2 100644
--- a/tests/Transceiver52M/Makefile.am
+++ b/tests/Transceiver52M/Makefile.am
@@ -1,6 +1,12 @@
 include $(top_srcdir)/Makefile.common
 
-AM_CFLAGS = -Wall -I$(top_srcdir)/Transceiver52M -I$(top_srcdir)/Transceiver52M/arch/common $(STD_DEFINES_AND_INCLUDES) -g
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/Transceiver52M \
+	-I$(top_srcdir)/Transceiver52M/arch/common \
+	$(STD_DEFINES_AND_INCLUDES) \
+	$(NULL)
+
+AM_CFLAGS = -Wall -g
 
 EXTRA_DIST = convolve_test.ok convolve_test_golden.h