package/gcc (arc): backport PR56780 patches

package/gcc (arc): backport PR56780 patches

--disable-install-libiberty configure option is broken
in gcc 4.8.x, so libiberty.a is always installed in HOST_DIR.

This library broke the host-gdb build due to a fpic/fPIC issue.

Note: host-binutils-arc-2014.12 install libiberty.a in HOST_DIR
but it was overwritten by the gcc one. The host-binutils's
libiberty.a also broke the host-gdb build. This should be
fixed in a followup patch.

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>