Shader: Fix conditional statement handling in partial compilation mode

include/Nazara/Shader/Ast/ExpressionType.hpp

@@ -166,6 +166,7 @@ namespace Nz::ShaderAst
 		ExpressionValue<StructLayout> layout;
 		std::string name;
 		std::vector<StructMember> members;
+		bool isConditional;
 	};
 
 	inline bool IsAliasType(const ExpressionType& type);

include/Nazara/Shader/Ast/SanitizeVisitor.hpp

@@ -218,6 +218,7 @@ namespace Nz::ShaderAst
 			{
 				std::size_t index;
 				IdentifierCategory category;
+				bool isConditional = false;
 			};
 
 			struct Identifier