I tried to build OpenJDK with GCC 15.0.1 on Fedora 42 x86_64, however I saw following error.

```
* For target support_native_java.desktop_libsplashscreen_splashscreen_gif.o:
/home/ysuenaga/github-forked/jdk/src/java.desktop/share/native/libsplashscreen/splashscreen_gif.c:51:41: error: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (12 chars into 11 available) [-Werror=unterminated-string-initialization]
   51 | static const char szNetscape20ext[11] = "NETSCAPE2.0";
      | ^~~~~~~~~~~~~
cc1: all warnings being treated as errors
```

This constant seems to be used to detect Netscape 2.0 extension in GIF image. It should be used to compare with extension block without NUL char, but we should tweak initialization to avoid this error for safety code.