Add builddir's src/ in header include path for config.h

tests/Makefile.am

@@ -17,7 +17,7 @@
 
 AM_CFLAGS = $(HWLOC_CFLAGS) -Wall $(STARPU_CUDA_CPPFLAGS) $(STARPU_OPENCL_CPPFLAGS)
 LIBS = $(top_builddir)/src/libstarpu.la $(HWLOC_LIBS) @LIBS@
-AM_CPPFLAGS = -I$(top_srcdir)/include/ -I$(top_srcdir)/src/
+AM_CPPFLAGS = -I$(top_srcdir)/include/ -I$(top_builddir)/src -I$(top_srcdir)/src/
 AM_LDFLAGS = $(STARPU_CUDA_LDFLAGS) $(STARPU_OPENCL_LDFLAGS)
 
 EXTRA_DIST =					\