Add a test that makes sure that the CBOR sources compile as C++

We'll need that in Qt and the Arduino AVR-GCC apparently does it too.

Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>
diff --git a/tests/cpp/cpp.pro b/tests/cpp/cpp.pro
new file mode 100644
index 0000000..b24047f
--- /dev/null
+++ b/tests/cpp/cpp.pro
@@ -0,0 +1,6 @@
+CONFIG += testcase parallel_test c++11
+QT = core testlib
+
+include(../../src/src.pri)
+SOURCES = tst_cpp.cpp
+