Add preprocessor

The parser now parses macros and inclusion directives.

src/libclang/preprocessor.hpp

@@ -0,0 +1,31 @@
+// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
+// This file is subject to the license terms in the LICENSE file
+// found in the top-level directory of this distribution.
+
+#ifndef CPPAST_PREPROCESSOR_HPP_INCLUDED
+#define CPPAST_PREPROCESSOR_HPP_INCLUDED
+
+#include <cppast/cpp_preprocessor.hpp>
+#include <cppast/libclang_parser.hpp>
+
+namespace cppast
+{
+    namespace detail
+    {
+        struct pp_entity
+        {
+            std::unique_ptr<cpp_entity> entity;
+            unsigned                    line;
+        };
+
+        struct preprocessor_output
+        {
+            std::string            source;
+            std::vector<pp_entity> entities;
+        };
+
+        preprocessor_output preprocess(const libclang_compile_config& config, const char* path);
+    }
+} // namespace cppast::detail
+
+#endif // CPPAST_PREPROCESSOR_HPP_INCLUDED