[gcc r12-7353] libgo: update README.gcc

[Ian Lance Taylor]

https://gcc.gnu.org/g:3d54f1ffaf77f9dfa75362f2228e6bbd191bcbc8

commit r12-7353-g3d54f1ffaf77f9dfa75362f2228e6bbd191bcbc8
Author: Ian Lance Taylor <iant@golang.org>
Date:   Tue Feb 22 15:04:06 2022 -0800

    libgo: update README.gcc
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/387514

Diff:
---
 gcc/go/gofrontend/MERGE | 2 +-
 libgo/README.gcc        | 7 +++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 7455d01c179..424bbebfeed 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-aee8eddbfc3ef1b03353a060e79e7d668fb229e2
+45fd14ab8baf5e86012a808426f8ef52c1d77943
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/libgo/README.gcc b/libgo/README.gcc
index d5aabb0f9c2..3c56ec7be17 100644
--- a/libgo/README.gcc
+++ b/libgo/README.gcc
@@ -1,7 +1,6 @@
 The files in this directory are mirrored from the gofrontend project
-hosted at http://code.google.com/p/gofrontend.  These files are the
+hosted at https://go.googlesource.com/gofrontend/ and mirrored at
+https://github.com/golang/gofrontend.  These files are the
 ones in the libgo subdirectory of that project.
 
-By default, the networking tests are not run.  In order to run all the
-libgo tests, you need to define the environment variable
-GCCGO_RUN_ALL_TESTS to a non-empty string.
+To change these files, see https://go.dev/doc/gccgo_contribute.