This patch reverts upstream commit b4d3485e4fc1d:

  https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=b4d3485e4fc1d029e620a59deb54b3f4f3f6b209

Otherwise, GCC ends up searching the wrong target directory for cross-headers.

diff --git a/gcc/configure b/gcc/configure
--- a/gcc/configure
+++ b/gcc/configure
@@ -3689,11 +3689,6 @@ esac
 fi
 
 
-# If both --with-sysroot and --with-gxx-include-dir are passed, we interpolate
-# the former in the latter and, upon success, compute gcc_gxx_include_dir as
-# relative to the sysroot.
-gcc_gxx_include_dir_add_sysroot=0
-
 # This logic must match libstdc++-v3/acinclude.m4:GLIBCXX_EXPORT_INSTALL_INFO.
 if test x${gcc_gxx_include_dir} = x; then
   if test x${enable_version_specific_runtime_libs} = xyes; then
@@ -3705,10 +3700,15 @@ if test x${gcc_gxx_include_dir} = x; then
     fi
     gcc_gxx_include_dir="\$(libsubdir)/\$(libsubdir_to_prefix)$libstdcxx_incdir"
   fi
-elif test "${with_sysroot+set}" = set; then
+fi
+
+gcc_gxx_include_dir_add_sysroot=0
+if test "${with_sysroot+set}" = set; then
   gcc_gxx_without_sysroot=`expr "${gcc_gxx_include_dir}" : "${with_sysroot}"'\(.*\)'`
   if test "${gcc_gxx_without_sysroot}"; then
-    gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    if test x${with_sysroot} != x/; then
+      gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    fi
     gcc_gxx_include_dir_add_sysroot=1
   fi
 fi
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 715fcba0482..88136e232df 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -204,11 +204,6 @@ no)	;;
 *)	gcc_gxx_include_dir=$with_gxx_include_dir ;;
 esac])
 
-# If both --with-sysroot and --with-gxx-include-dir are passed, we interpolate
-# the former in the latter and, upon success, compute gcc_gxx_include_dir as
-# relative to the sysroot.
-gcc_gxx_include_dir_add_sysroot=0
-
 # This logic must match libstdc++-v3/acinclude.m4:GLIBCXX_EXPORT_INSTALL_INFO.
 if test x${gcc_gxx_include_dir} = x; then
   if test x${enable_version_specific_runtime_libs} = xyes; then
@@ -220,10 +215,15 @@ if test x${gcc_gxx_include_dir} = x; then
     fi
     gcc_gxx_include_dir="\$(libsubdir)/\$(libsubdir_to_prefix)$libstdcxx_incdir"
   fi
-elif test "${with_sysroot+set}" = set; then
+fi
+
+gcc_gxx_include_dir_add_sysroot=0
+if test "${with_sysroot+set}" = set; then
   gcc_gxx_without_sysroot=`expr "${gcc_gxx_include_dir}" : "${with_sysroot}"'\(.*\)'`
   if test "${gcc_gxx_without_sysroot}"; then
-    gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    if test x${with_sysroot} != x/; then
+      gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    fi
     gcc_gxx_include_dir_add_sysroot=1
   fi
 fi
/th></tr>
<tr><td><span title='2023-08-20 02:00:00 +0200'>2023-08-20</span></td><td><a href='/guix/commit/gnu/system/accounts.scm?id=5a2c3352d8f8a08a5ba01542a3f282799e503d33'>Revert "gnu: system: Add home-directory-permissions field to &lt;user-account&gt;."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit e9a5eebc785cb843034b38c5c5a6dd10904bdf2a, which
as far as I can tell breaks system roll-backs thusly:

[...]
In gnu/build/accounts.scm:
   239:27  3 (_ #&lt;&lt;password-entry&gt; name: "root" password: "x" uid: 0 gid: 0 real-name: "System &gt;)
In unknown file:
           2 (string-join ("root" "x" "0" "0" "System administrator" "/root" #t) ":" #&lt;undefined&gt;)
In ice-9/boot-9.scm:
  1685:16  1 (raise-exception _ #:continuable? _)
  1685:16  0 (raise-exception _ #:continuable? _)

ice-9/boot-9.scm:1685:16: In procedure raise-exception:
In procedure string-append: Wrong type (expecting string): #t
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2023-08-25 15:12:54 +0200'>2023-08-25</span></td><td><a href='/guix/commit/gnu/system/accounts.scm?id=e9a5eebc785cb843034b38c5c5a6dd10904bdf2a'>gnu: system: Add home-directory-permissions field to &lt;user-account&gt;.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/accounts.scm (&lt;user-account&gt;)[home-directory-permissions]: New
field.
(user-account-home-directory-permissions): New accessor.
* gnu/build/activation.scm (activate-users+groups): Use home directory
permission bits from the user account object.
* doc/guix.texi (User Accounts): Document new field.

Signed-off-by: Josselin Poiret &lt;dev@jpoiret.xyz&gt;
</span></span></td><td>David Thompson</td></tr>
<tr><td><span title='2023-07-26 10:40:16 -0400'>2023-07-26</span></td><td><a href='/guix/commit/gnu/system/accounts.scm?id=03795e2ba27424fc98957da00f6c71325e7ae425'>system: accounts: Export &lt;user-account&gt;.</a></td><td>Maxim Cournoyer</td></tr>