diff --git a/gcc/config/rs6000/linux.h b/gcc/config/rs6000/linux.h
index a3f87d962017..19f939f7a694 100644
--- a/gcc/config/rs6000/linux.h
+++ b/gcc/config/rs6000/linux.h
@@ -25,6 +25,9 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #define CPP_PREDEFINES \
  "-DPPC -D__ELF__ -Dunix -Dlinux -Dpowerpc -Asystem(unix) -Asystem(linux) -Acpu(powerpc) -Amachine(powerpc)"
 
+#undef	CPP_OS_DEFAULT_SPEC
+#define CPP_OS_DEFAULT_SPEC "%(cpp_os_linux)"
+
 #undef LINK_SPEC
 #define LINK_SPEC "-m elf32ppc %{G*} %{shared:-shared} \
   %{!shared: \