[EXAMPLE:F0] Add usart printf example using newlib-nano

examples/stm32/f0/stm32f0-discovery/usart_stdio/Makefile

@@ -0,0 +1,29 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = usart_stdio
+
+LDSCRIPT = ../stm32f0-discovery.ld
+
+#using newlib-nano
+CFLAGS += --specs=nano.specs
+LDFLAGS += --specs=nano.specs
+
+include ../../Makefile.include
+