From: Federico Ceratto <federico@debian.org>
Subject: Enable hardening flags, fix build

--- a/SConstruct
+++ b/SConstruct
@@ -130,3 +130,5 @@
 )
 
 env.Program(target='goxel', source=sources)
+env.Append(CFLAGS='-Wformat-security -Werror=format-security -fPIE')
+env.Append(CFLAGS='-Wno-error=format-overflow=')
