reduce libfibre binary size

Firmware/fibre-cpp/Makefile

@@ -43,4 +43,4 @@ windows:
 		-static-libgcc -Wl,-Bstatic -lstdc++ ./third_party/libusb-windows/libusb-1.0.23/MinGW64/static/libusb-1.0.a -Wl,-Bdynamic
 
 # To check exported symbols run:
-#   nm -D libfibre.so | grep T
+#   nm -D libfibre.so | grep ' T '

Firmware/fibre-cpp/compile_for_all_platforms.sh

@@ -11,6 +11,9 @@ set -euo pipefail
 
 # TODO: support C++11
 
+CROSS_PLATFORM_CFLAGS='-O3 -fPIC -std=c++11 -DFIBRE_COMPILE -DFIBRE_ENABLE_CLIENT'
+CROSS_PLATFORM_GCC_FLAGS='-flto -Wl,--version-script=libfibre.version -Wl,--gc-sections'
+
 mkdir -p third_party
 
 # Usage: download_deb_pkg destination-dir url
@@ -68,12 +71,17 @@ FILES=('libfibre.cpp'
 
 function build_for_linux() {
     arch_name="$1"
-    "${CXX}" -shared -o libfibre-"$arch_name".so -fPIC -std=c++11 -I./include -DFIBRE_COMPILE -DFIBRE_ENABLE_CLIENT \
+    "${CXX}" -shared -o libfibre-"$arch_name".so -I./include \
             ${CFLAGS} \
+            ${CROSS_PLATFORM_CFLAGS} \
+            ${CROSS_PLATFORM_GCC_FLAGS} \
     		"${FILES[@]}" \
             ${LIBS} \
             -lpthread \
             -Wl,--unresolved-symbols=ignore-in-shared-libs -static-libstdc++
+    
+    # Could reduce binary size by 35% by using something like
+    #arm-none-eabi-strip --strip-all --discard-all libfibre-linux-armhf.so
 }
 
 
@@ -117,16 +125,22 @@ CXX="arm-linux-gnueabihf-g++" \
 ### Windows
 
 echo "building libfibre for Windows (AMD64)..."
-x86_64-w64-mingw32-g++ -shared -o libfibre-windows-amd64.dll -fPIC -std=c++11 -I./include -DFIBRE_COMPILE -DFIBRE_ENABLE_CLIENT \
+x86_64-w64-mingw32-g++ -shared -o libfibre-windows-amd64.dll -I./include \
         -I./third_party/libusb-windows/libusb-1.0.23/include/libusb-1.0 \
+        ${CROSS_PLATFORM_CFLAGS} \
+        ${CROSS_PLATFORM_GCC_FLAGS} \
         "${FILES[@]}" \
         -static-libgcc \
         -Wl,-Bstatic \
         -lstdc++ \
         ./third_party/libusb-windows/libusb-1.0.23/MinGW64/static/libusb-1.0.a \
-        -Wl,-Bdynamic        
+        -Wl,-Bdynamic
 cp /usr/x86_64-w64-mingw32/bin/libwinpthread-1.dll .
 
+# The windows compiler keeps a ton of debug symbols for some reason. Stripping
+# the DLL reduces its size by a factor of 10.
+x86_64-w64-mingw32-strip --strip-all --discard-all libfibre-windows-amd64.dll
+
 ### macOS
 
 # Link are broken:
@@ -152,11 +166,12 @@ export MACOSX_DEPLOYMENT_TARGET='10.9'
 CC='o64-clang' \
     compile_libusb 'macos-amd64' 'x86_64-apple-darwin17'
 
-echo "building libfibre for macOS"
+echo "building libfibre for macOS (x86)"
 
-o64-clang++ -shared -o libfibre-macos-x86.dylib -fPIC -std=c++11 -I./include -DFIBRE_COMPILE -DFIBRE_ENABLE_CLIENT \
+o64-clang++ -shared -o libfibre-macos-x86.dylib -I./include \
         -I./third_party/libusb-windows/libusb-1.0.23/include/libusb-1.0 \
         -arch x86_64 -arch i386 \
+        ${CROSS_PLATFORM_CFLAGS} \
         "${FILES[@]}" \
         -static-libstdc++ \
         ./third_party/libusb-1.0.23/build-macos-amd64/libusb/.libs/libusb-1.0.a \

Firmware/fibre-cpp/libfibre.version

@@ -0,0 +1,4 @@
+LIBFIBREABI_0.1.0 {
+    global: libfibre_*;
+    local: *;
+};