Generate board-specific gdb wrapper script.

This adds the code to generate gdb-${board}, the gdb wrapper script
that calls cros_gdb (in chromite) with the appropriate flags/options.

BUG=chromium:361767
TEST=Ran setup_board and it generated the wrapper script properly.

CQ-DEPEND=CL:234832

Change-Id: I6e2364ee80e9a3d618c297b075d52fb04e02631f
Reviewed-on: https://chromium-review.googlesource.com/234638
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
diff --git a/setup_board b/setup_board
index c7ac454..dfb775f 100755
--- a/setup_board
+++ b/setup_board
@@ -157,6 +157,13 @@
 EOF
   wrappers+=( "${wrapper}" )
 
+  wrapper="/usr/local/bin/gdb-${BOARD_VARIANT}"
+  sudo_clobber "${wrapper}" <<EOF
+#!/bin/sh
+exec cros_gdb --board="${BOARD_VARIANT}" "\$@"
+EOF
+  wrappers+=( "${wrapper}" )
+
   cmds+=(
     "chmod a+rx ${wrappers[*]}"
     "chown root:root ${wrappers[*]}"