[opengl] fix GL_NV_geometry_shader_passthrough compiler complaints (#3357)

this can be seen immediately on startup of switch sports where the passthru geometry shader will spectacularly fail to compile because the driver complains about re-declaration

this is just a simple and quickie fix for that

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3357
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: DraVee <dravee@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/shader_recompiler/backend/glsl/glsl_emit_context.cpp

@@ -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: Copyright 2021 yuzu Emulator Project
@@ -298,10 +298,12 @@ EmitContext::EmitContext(IR::Program& program, Bindings& bindings, const Profile
         stage_name = "gs";
         header += fmt::format("layout({})in;", InputPrimitive(runtime_info.input_topology));
         if (uses_geometry_passthrough) {
-            header += "layout(passthrough)in gl_PerVertex{vec4 gl_Position;};";
+            // Passthru REQUIRES the layout to be defined with a corresponding name, for our sanity
+            // we will just use `gl_in[]`, if you don't the driver will complain with:
+            // 0(56) : error C7593: Builtin block member gl_Position not found in redeclaration of in gl_PerVertex
+            header += "layout(passthrough)in gl_PerVertex{vec4 gl_Position;}gl_in[];";
             break;
-        } else if (program.is_geometry_passthrough &&
-                   !profile.support_geometry_shader_passthrough) {
+        } else if (program.is_geometry_passthrough && !profile.support_geometry_shader_passthrough) {
             LOG_WARNING(Shader_GLSL, "Passthrough geometry program used but not supported");
         }
         header += fmt::format(