Comment # 14 on bug 936463 from Richard Biener

(In reply to Stanislav Brabec from comment #13)
> Created attachment 639727 [details]
> Proposed fix for 2)
> 
> I have an easy fix for 2)
> 
> However I have a problem:
> 
> It compiled libgcc.a and others several hours ago. But now sources in
> Factory are newer than compiler there, and it does not compile. I am not
> sure, whether it is a temporary rebuild problem. Let's see tomorrow.
> 
> https://build.opensuse.org/project/monitor/home:sbrabec:branches:devel:gcc

This generally doesn't work as most targets need glibc headers to build
target libraries and using the glibc headers from the host is wrong here
(thus for avr you'd need to BuildRequire avr-libc which should install
into the avr sysroot).

the %gcc_icecream 1 path is especially meant to not build target libraries
but only host binaries - those binaries now also get packaged as cross-*-gcc5
for easy access as requested by kernel developers who do _not_ need target
libraries.

Andreas did some preliminary work to build real cross-compilers for the
non %gcc_icecream path.  Thus as a first step to build target libraries for
avr you'd need to change change_spec like

Index: change_spec
===================================================================
--- change_spec (revision 64)
+++ change_spec (working copy)
@@ -133,7 +133,7 @@
 add_cross cross-aarch64-gcc$base_ver aarch64 aarch64-suse-linux %define
gcc_icecream 1
 add_cross cross-armv6hl-gcc$base_ver armv6hl armv6hl-suse-linux-gnueabi
%define gcc_icecream 1
 add_cross cross-armv7hl-gcc$base_ver armv7hl armv7hl-suse-linux-gnueabi
%define gcc_icecream 1
-add_cross cross-avr-gcc$base_ver avr avr-suse-linux %define gcc_icecream 1
+add_cross cross-avr-gcc$base_ver avr avr
 add_cross cross-i386-gcc$base_ver i386 i586-suse-linux %define gcc_icecream 1
 add_cross cross-x86_64-gcc$base_ver x86_64 x86_64-suse-linux %define
gcc_icecream 1
 add_cross cross-s390-gcc$base_ver s390 s390-suse-linux %define gcc_icecream 1

thus drop the gcc_icecream define for avr.  You'll then run into

make %{?jobs:-j%jobs}

which might or might not succeed.  You also get a proper sysroot defined
automagically (you have to double-check whether that agrees with the
binutils one)