tests: fixup minor autotools nit

Makes super strict builds fail due to a warning.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

diff --git a/tests/Makefile.am b/tests/Makefile.am
index aefe0d06ac556e09059e38a582fe5c4403638bca..9b60312cef61603cc65ebbb3373831c1930f8631 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -3,7 +3,7 @@ include ../common.am
 PYTHON ?= python
 
 AUTOMAKE_OPTIONS = subdir-objects
-AM_CPPFLAGS = \
+AM_CPPFLAGS += \
        -I.. \
        -I$(top_srcdir) \
        -I$(top_srcdir)/lib \