shader_recompiler,video_core: Cleanup some GCC and Clang errors

Mostly fixing unused *, implicit conversion, braced scalar init,
fpermissive, and some others.

Some Clang errors likely remain in video_core, and std::ranges is still
a pertinent issue in shader_recompiler

shader_recompiler: cmake: Force bracket depth to 1024 on Clang
Increases the maximum fold expression depth

thread_worker: Include condition_variable

Don't use list initializers in control flow

Co-authored-by: ReinUsesLisp <reinuseslisp@airmail.cc>

src/shader_recompiler/CMakeLists.txt

@@ -196,6 +196,8 @@ else()
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-parameter>
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-variable>
         -Werror=unused-variable
+
+        $<$<CXX_COMPILER_ID:Clang>:-fbracket-depth=1024>
     )
 endif()