Use github's mirror for sourceware's repo

We use shallow clones to reduce the clone time, however that fesature
seems not well supported on sourceware's server, so we use github's
mirror instead.

Author: kito-cheng

.gitmodules

@@ -1,16 +1,19 @@
+# Some of the external git repos are not upstream servers but upstream clones to
+# avoid "Server does not allow request for unadvertised object" errors (see
+# #1654).
 [submodule "binutils"]
 	path = binutils
-	url = https://sourceware.org/git/binutils-gdb.git
+	url = https://github.com/bminor/binutils-gdb.git
 	branch = binutils-2_44-branch
 	shallow = true
 [submodule "gcc"]
 	path = gcc
-	url = https://gcc.gnu.org/git/gcc.git
+	url = https://github.com/gcc-mirror/gcc.git
 	branch = releases/gcc-14
 	shallow = true
 [submodule "glibc"]
 	path = glibc
-	url = https://sourceware.org/git/glibc.git
+	url = https://github.com/bminor/glibc.git
 	shallow = true
 [submodule "dejagnu"]
 	path = dejagnu
@@ -19,12 +22,12 @@
 	shallow = true
 [submodule "newlib"]
 	path = newlib
-	url = https://sourceware.org/git/newlib-cygwin.git
+	url = https://github.com/bminor/newlib.git
 	branch = master
 	shallow = true
 [submodule "gdb"]
 	path = gdb
-	url = https://sourceware.org/git/binutils-gdb.git
+	url = https://github.com/bminor/binutils-gdb.git
 	branch = gdb-15-branch
 	shallow = true
 [submodule "qemu"]