-AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_builddir)/include -I$(top_srcdir)/src
+AM_CPPFLAGS += -I$(top_srcdir)/include -I$(top_builddir)/include -I$(top_srcdir)/src
-noinst_HEADERS = cpuset.h thread-id.h
+noinst_HEADERS = thread-id.h
noinst_LTLIBRARIES = libdebug-yield.la