patch docs to suggest using LD_LIBRARY_PATH to find libgmp.so etc.

[Ralf Wildenhues]

* Jonathan Wakely wrote on Sun, Sep 26, 2010 at 04:46:08PM CEST:
> > http://gcc.gnu.org/PR45760 is the latest example of users not
> > realising that libgmp.so, libmpfr.so and libmpc.so need to be found
> > while bootstrapping.
> >
> > This patch adds a note to the --with-gmp docs pointing out the
> > requirement and suggesting to use LD_LIBRARY_PATH.
> >
> > OK for trunk?
> >
> > 2010-09-25  Jonathan Wakely  <jwakely.gcc@gmail.com>
> >
> > Â  Â  Â  Â * doc/install.texi: Suggest using LD_LIBRARY_PATH to find libs
> > Â  Â  Â  Â for GMP, MPFR and MPC.

The shlibpath_var (that's what libtool calls the variable which on
GNU/Linux and Solaris is LD_LIBRARY_PATH) can have different names
on different systems, see
  grep shlibpath_var= libtool.m4

In the general configuration section, I think the language should be
more generic.

Actually, I would suggest to *optionally* also allow hard-coding
needed paths into generated executables, but I understand I'm leaning
quite far out of the window already ...

Thanks,
Ralf