Optimize newlib binaries size (nano variant) (#20)

Reduce newlib size (-Os and lightweight IO formatting)

Saves ~40KB of .text in final binaries built using toolchain.

Co-authored-by: dkulacz <dkulacz>

Dockerfile

@@ -95,9 +95,11 @@ RUN mkdir -p ${BUILD_PATH}/gcc && \
 # build newlib
 RUN mkdir -p ${BUILD_PATH}/newlib && \
     cd ${BUILD_PATH}/newlib && \
+    export CFLAGS_FOR_TARGET="-Os" && \
     ${SOURCES_PATH}/newlib-${NEWLIB_VERSION}/configure \
         --target=${TARGET_ARCH} \
         --prefix=${TOOLCHAIN_PATH} \
+        --enable-newlib-nano-formatted-io \
         --disable-nls \
     && \
     make -j$(nproc) all && \

build-gcc-v850-elf-toolchain.sh

@@ -101,9 +101,11 @@ make -w install-gcc 2>&1 | tee make.out
 mkdir -p ${BUILD_PATH}/newlib
 cd ${BUILD_PATH}/newlib
 
+export CFLAGS_FOR_TARGET="-Os"
 ${SOURCES_PATH}/newlib-${NEWLIB_VERSION}/configure \
 --target=${TARGET_ARCH} \
 --prefix=${TOOLCHAIN_PATH} \
+--enable-newlib-nano-formatted-io \
 --disable-nls \
 -v 2>&1 | tee configure.out