[gcc r13-6534] docs: Add link to gmplib.org.

[gcc r13-6534] docs: Add link to gmplib.org.

[Sandra Loosemore]

https://gcc.gnu.org/g:c7867f82f4c08fb355bb0115ade51df8fdbe3832

commit r13-6534-gc7867f82f4c08fb355bb0115ade51df8fdbe3832
Author: Benson Muite <benson_muite@emailplus.org>
Date:   Tue Mar 7 21:48:20 2023 +0000

    docs: Add link to gmplib.org.
    
    gcc/ChangeLog
            * doc/install.texi (Prerequisites): Add link to gmplib.org.

Diff:
---
 gcc/doc/install.texi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 9133c8f8543..f549ba597cb 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -396,7 +396,8 @@ install the libraries.
 @table @asis
 @item GNU Multiple Precision Library (GMP) version 4.3.2 (or later)
 
-Necessary to build GCC@.  If a GMP source distribution is found in a
+Necessary to build GCC@.  It can be downloaded from
+@uref{https://gmplib.org/}.  If a GMP source distribution is found in a
 subdirectory of your GCC sources named @file{gmp}, it will be built
 together with GCC.  Alternatively, if GMP is already installed but it
 is not in your library search path, you will have to configure with the