CI updates and minor cleanups

src/file.h

@@ -88,6 +88,8 @@ public:
     virtual upx_off_t seek(upx_off_t off, int whence) override;
     upx_off_t st_size_orig() const;
 
+    noinline int dup() may_throw;
+
 protected:
     upx_off_t _length_orig = 0;
 };