Changes to overlay_shader.cc workaround a bug in GCC-12.2
(likely a duplicate of [0]). As the workaround involved removing
a local variable which most functions already didn't assign,
remove it for all functions.
An alternative is to add (otherwise redundant) parenthesis, e.g.
`&(e_data.sh_data[sh_cfg])`, but this would need to be noted in
code-comments, so opt for removing the intermediate variable.
[0]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106247
e1aef2e87e