Makefile.in FLAGS_TO_PASS: why pass *_FOR_TARGET variables?

[David Edelsohn]

	I am not refering to the top-level Makefile -- I am sorry that I
did not make that more clear.  All of my comments were in reference to
gcc/Makefile.in . 

	All of the issues make sense for the top-level Makefile and it
seems to define things sensibly.  Which variables are passed and the lack
of use of those variables in subsidiary Makefiles does not make sense in
gcc/Makefile.

David