Added security flags for the release build

Makefile

@@ -54,8 +54,8 @@ debug_executable: CXXFLAGS += -DDEBUG -g
 debug_executable: build $(APP_DIR)/$(TARGET)
 	gdb $(APP_DIR)/$(TARGET)
 
-release_executable: CFLAGS += -O3 -march=native
-release_executable: CXXFLAGS += -O3 -march=native
+release_executable: CFLAGS += -O2 -march=native -D_FORTIFY_SOURCE=2 -fstack-protector-strong --param ssp-buffer-size=4 -fPIE -pie -Wl,-z,relro,-z,now
+release_executable: CXXFLAGS += -O2 -march=native -D_FORTIFY_SOURCE=2 -fstack-protector-strong --param ssp-buffer-size=4 -fPIE -pie -Wl,-z,relro,-z,now
 release_executable: build $(APP_DIR)/$(TARGET)
 
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