Do not pass -dynamic-linker to linker when !shared.
Fixes <http://bugs.gnu.org/20102>.

ARM 'link' spec issue reported at
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65711 and
https://gcc.gnu.org/ml/gcc-patches/2015-04/msg01387.html.

Patch by Ludovic Courtès <ludo@gnu.org>.

--- gcc-4.8.4/gcc/config/arm/linux-elf.h.orig	2015-04-08 20:31:20.376900478 +0200
+++ gcc-4.8.4/gcc/config/arm/linux-elf.h	2015-04-08 20:31:36.437014437 +0200
@@ -65,7 +65,7 @@
    %{symbolic:-Bsymbolic} \
    %{!static: \
      %{rdynamic:-export-dynamic} \
-     -dynamic-linker " GNU_USER_DYNAMIC_LINKER "} \
+     %{!shared:-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}} \
    -X \
    %{mbig-endian:-EB} %{mlittle-endian:-EL}" \
    SUBTARGET_EXTRA_LINK_SPEC
