[gcc r12-6667] Update prerequisites for GNAT

[Arnaud Charlet]

https://gcc.gnu.org/g:abb748aaf3e1d25258949856d5b39f6ac90a8119

commit r12-6667-gabb748aaf3e1d25258949856d5b39f6ac90a8119
Author: Arnaud Charlet <charlet@adacore.com>
Date:   Tue Jan 18 05:44:40 2022 -0500

    Update prerequisites for GNAT
    
            * doc/install.texi: Update prerequisites for GNAT

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

diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 54ad7c7b47c..96b4dfc871a 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -263,7 +263,7 @@ name of the package depends on your distro) or you must build GCC as a
 @item @anchor{GNAT-prerequisite}GNAT
 
 In order to build GNAT, the Ada compiler, you need a working GNAT
-compiler (GCC version 4.7 or later).
+compiler (GCC version 5.1 or later).
 
 This includes GNAT tools such as @command{gnatmake} and
 @command{gnatlink}, since the Ada front end is written in Ada and