Enable function and data sections for newlib.

Reduces size of hello in freedom-e-sdk by ~10 kb (20%), if also
linking with --gc-sections.

Author: brucehoult

Makefile.in

@@ -384,7 +384,7 @@ stamps/build-newlib: $(srcdir)/riscv-newlib stamps/build-gcc-newlib-stage1
 		--enable-newlib-io-long-double \
 		--enable-newlib-io-long-long \
 		--enable-newlib-io-c99-formats \
-		CFLAGS_FOR_TARGET="-Os $(CFLAGS_FOR_TARGET)"
+		CFLAGS_FOR_TARGET="-Os -ffunction-sections -fdata-sections $(CFLAGS_FOR_TARGET)"
 	$(MAKE) -C $(notdir $@)
 	$(MAKE) -C $(notdir $@) install
 	mkdir -p $(dir $@) && touch $@