libgcc: add crt{begin,end} for powerpc-wrs-vxworks target

In order to allow ZCX on VxWorks, we need the frame_dummy function to do
the register_frame_info(). So make sure crtbegin.o and crtend.o are
available for use with a custom spec file.

From-SVN: r263690

libgcc/ChangeLog

@@ -1,3 +1,8 @@
+2018-08-21  Rasmus Villemoes  <rv@rasmusvillemoes.dk>
+
+	* config.host: Add crtbegin.o and crtend.o for
+	powerpc-wrs-vxworks target.
+
 2018-08-17  Jojo  <jijie_rong@c-sky.com>
 	    Huibin Wang  <huibin_wang@c-sky.com>
 	    Sandra Loosemore  <sandra@codesourcery.com>

libgcc/config.host

@@ -1141,6 +1141,7 @@ powerpc*-*-linux*)
 	;;
 powerpc-wrs-vxworks*)
 	tmake_file="$tmake_file rs6000/t-ppccomm rs6000/t-savresfgpr t-fdpbit"
+	extra_parts="$extra_parts crtbegin.o crtend.o"
 	;;
 powerpc-*-lynxos*)
 	tmake_file="$tmake_file rs6000/t-lynx t-fdpbit"