message: Don't reject macro definitions in system headers
  Before, an assert() macro expansion jumps to __assert_fail but not
  assert. This is because OnIndexReference finds a reference to __assert_fail
  but VisitMacroDefinitionAndExpansions rejects the expansion.
diff: @@ -923,9 +923,6 @@ ClangCursor::VisitResult VisitMacroDefinitionAndExpansions(ClangCursor cursor,
  // Resolve location, find IndexFile instance.
  CXSourceRange cx_source_range =
  clang_Cursor_getSpellingNameRange(cursor.cx_cursor, 0, 0);
  - CXSourceLocation start = clang_getRangeStart(cx_source_range);
  - if (clang_Location_isInSystemHeader(start))
  - break;
  CXFile file;
  Range decl_loc_spelling = Resolve(cx_source_range, &file);
  IndexFile* db = ConsumeFile(param, file);
  