Bug#989453:

[Alexey Brodkin <Alexey.Brodkin@synopsys.com>]

With GCC updated to v11.x most of mentioned above patches became a part
of the upstream release so no longer needed.

And the only thing which we really need in Debian is to disable multilib as we don't
support multilib for ARC in glibc and so need to disable multilib explicitly in GCC
to eliminate problems with multiple libs, their paths etc and just have one and only
supported default configuration. That is done as simple as that:
----------------------------------
diff --git a/debian/rules2 b/debian/rules2
index 750c03f..880a63e 100644
--- a/debian/rules2
+++ b/debian/rules2
@@ -466,6 +466,10 @@ ifneq (,$(findstring arm-vfp,$(DEB_TARGET_GNU_CPU)))
   CONFARGS += --with-fpu=vfp
 endif

+ifneq (,$(findstring arc-linux,$(DEB_TARGET_GNU_TYPE)))
+  CONFARGS += --disable-multilib
+endif
+
 ifneq (,$(findstring arm, $(DEB_TARGET_GNU_CPU)))
   ifeq ($(multilib),yes)
     CONFARGS += --enable-multilib
----------------------------------

Please consider applying it.

-Alexey