[CLANG-TIDY] readability-redundant-preprocessor

.clang-tidy

@@ -42,6 +42,7 @@ readability-misplaced-array-index,
 readability-redundant-control-flow,
 readability-redundant-declaration,
 readability-redundant-function-ptr-dereference,
+readability-redundant-preprocessor,
 readability-redundant-smartptr-get,
 readability-redundant-string-cstr,
 readability-simplify-subscript-expr,

src/core/load_balancing/MetisWrapper.cpp

@@ -54,9 +54,7 @@
 #  endif
 #endif
 
-#ifdef WALBERLA_BUILD_WITH_METIS
-#  include "metis.h"
-#endif
+#include "metis.h"
 
 #ifdef _MSC_VER
 #  pragma pop_macro( "INT64_MAX" )
@@ -185,4 +183,4 @@ const int METIS_OPTION_UBVEC      = 0;
 
 
 } // namespace core
-} // namespace walberla
\ No newline at end of file
+} // namespace walberla