[cmake] fixes for XCode when having languages other than C/C++ (#3772)

Signed-off-by: lizzie <lizzie@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3772
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/shader_recompiler/CMakeLists.txt

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2018 yuzu Emulator Project
@@ -253,8 +253,7 @@ if (MSVC)
     )
 else()
     target_compile_options(shader_recompiler PRIVATE
-        -Werror=conversion
-
+        $<$<COMPILE_LANGUAGE:C,CXX>:-Werror=conversion>
         # Bracket depth determines maximum size of a fold expression in Clang since 9c9974c3ccb6.
         # And this in turns limits the size of a std::array.
         $<$<CXX_COMPILER_ID:Clang>:-fbracket-depth=1024>