Test no namespace and custom namespace on CI

.travis/script-linux.sh

@@ -7,8 +7,14 @@ _FLAGS="-Werror"
 export CFLAGS="${_FLAGS}"
 export CXXFLAGS="${_FLAGS}"
 
-# Start clean
+echo "==============> Normal build"
 make clean >/dev/null
-
-# Build now
 make
+
+echo "==============> No namespace build"
+make clean >/dev/null
+make CXXFLAGS="${_FLAGS} -DDONT_SET_USING_DISTRHO_NAMESPACE"
+
+echo "==============> Custom namespace build"
+make clean >/dev/null
+make CXXFLAGS="${_FLAGS} -DDISTRHO_NAMESPACE=WubbWubb -DDGL_NAMESPACE=DabDab"