Reduce helper binary size

Signed-off-by: Sean Du <do4suki@gmail.com>

CMakeLists.txt

@@ -80,3 +80,10 @@ if(MINGW)
         "-static-libstdc++"
     )
 endif()
+
+if(CMAKE_BUILD_TYPE STREQUAL "Release")
+    target_link_options(cgss-borderless-helper PRIVATE
+        "-Wl,--gc-sections"
+        "-s"
+    )
+endif()

Makefile

@@ -26,6 +26,7 @@ else
   CFLAGS += -O2 -ffunction-sections -fdata-sections
   CXXFLAGS += -O2 -ffunction-sections -fdata-sections
   LDFLAGS += -Wl,--gc-sections -s
+  HELPER_LDFLAGS += -Wl,--gc-sections -s
 endif
 
 C_SRCS := \