shader: Implement NDC [-1, 1], attribute types and default varying initialization

src/shader_recompiler/CMakeLists.txt

@@ -14,6 +14,7 @@ add_library(shader_recompiler STATIC
     backend/spirv/emit_spirv_logical.cpp
     backend/spirv/emit_spirv_memory.cpp
     backend/spirv/emit_spirv_select.cpp
+    backend/spirv/emit_spirv_special.cpp
     backend/spirv/emit_spirv_undefined.cpp
     backend/spirv/emit_spirv_vote.cpp
     environment.h