+# apply unconditional per-directory flags
+define add_IS_IN_lib
+ifneq ($(strip $(2)),)
+__add_IS_IN_lib := $(subst $(top_builddir),,$(2))
+$$(__add_IS_IN_lib): CFLAGS-for-library-members:=$(CFLAGS-$(1)) -DIN_LIB=$(word 1,$(subst /, ,$(1)))
+endif
+endef
+$(eval $(call add_IS_IN_lib,rtld,$(ldso-y)))
+$(eval $(call add_IS_IN_lib,libc,$(libc-y) $(libc-static-y) $(libc-y:.o=.os) $(libc-shared-y) $(libc-nonshared-y)))
+$(eval $(call add_IS_IN_lib,libcrypt,$(libcrypt-a-y) $(libcrypt-so-y)))
+$(eval $(call add_IS_IN_lib,libdl,$(libdl-a-y) $(libdl-so-y)))
+$(eval $(call add_IS_IN_lib,libintl,$(libintl-a-y) $(libintl-so-y)))
+$(eval $(call add_IS_IN_lib,libm,$(libm-a-y) $(libm-so-y)))
+$(eval $(call add_IS_IN_lib,libnsl,$(libnsl-a-y) $(libnsl-so-y)))
+$(eval $(call add_IS_IN_lib,libpthread/$(PTNAME),$(libpthread-a-y) $(libpthread-so-y) $(libpthread-nonshared-y)))
+$(eval $(call add_IS_IN_lib,libpthread/$(PTNAME)_db,$(libthread_db-a-y) $(libthread_db-so-y)))
+$(eval $(call add_IS_IN_lib,libresolv,$(libresolv-a-y) $(libresolv-so-y)))
+$(eval $(call add_IS_IN_lib,librt,$(librt-a-y) $(librt-so-y)))
+$(eval $(call add_IS_IN_lib,libutil,$(libutil-a-y) $(libutil-so-y)))
+$(eval $(call add_IS_IN_lib,libubacktrace,$(libubacktrace-a-y) $(libubacktrace-so-y)))
+