Fix GDB build on ArchLinux

Archlinux provides both, libguile v2.0 and v2.2. GDB states in
configuration its compatibility with both versions of libguile which is
false. The SCM_port interface of libguile was removed in v2.2 and
therefore breaks GDB as a user.

RTEMS does not use libguile and therefore it can be compiled without
support.

https://sourceware.org/bugzilla/show_bug.cgi?id=21104

Close #3054.

source-builder/config/gdb-7-1.cfg

@@ -119,6 +119,7 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
     %{?gdb-sim-options:%{gdb-sim-options}} \
     --without-zlib \
     --with-expat \
+    --with-guile=no \
     %{!?without_python:%{with_python_option}} \
     --prefix=%{_prefix} --bindir=%{_bindir} \
     --exec-prefix=%{_exec_prefix} \