This patch has both a toplevel part and a part in gcc/, so I don't
know exactly who can approve it.
I haven't really understood why you need this patch.
If you need to set the LD_LIBRARY_PATH manually after installation,
something is broken. If the GMPLIBSDIR is for example something in your
home directory, the solution is not to patch gcc and maybe other
mpfr-using programs that you are a developer of: rather, the solution is
to add $HOME/lib to the search path in your .profile file.
If you need this patch because you're running `make check' with a
non-installed copy of gmp/mpfr, I'm not sure this is something that we
want to support. It would be a different story, of course, if mpfr
could be dropped into a unified tree and the in-tree mpfr would be used
by GCC: but in this case the in-tree mpfr would be added to the
LD_LIBRARY_PATH automatically, just like libbfd is.
As a side note, making an in-tree mpfr possible is something easy to do,
that I'd endorse, and that I could help with (unlike moving libgcc to
the toplevel ;-).
Or did I miss the point entirely?
Paolo