@@ Messages during configuration should be about 80 chars long.
   Right now they are much shorter which makes it look really ugly.

@@ some keywords (l:) are being framed

%% Relative paths result in rebuilds.

@% When configuring with -j N some strange warnings appear. Temporary
   fix. Depends on GNU make bug #12229.

%% Use src_root path as default value for out_root.

@@ Intel C++ does not generate phony rule for non-existent headers.

@@ It seems to me that in generated header prefix logic the dependency
   patched by sed script and one produced by a subsequent run of the
   compiler are different which triggers makefile reload. I wonder
   why?