fix gen_links.sh: don't include source dir as link target

First of all, use one common place to define the gen_links() macro, in
gen_links.sh.inc.

In this new file, add a 'shift' to exclude the $DIR arg from also appearing in
$FILES.

This prevents the following wrong symlinks in the source dirs:

  M3UA_CNL113537/src/src
  MTP3asp_CNL113337/src/src
  SCCP_CNL113341/src/src

Change-Id: Ia8493e77df1ba8723f2c5d2a49816247b0fb55f7
13 files changed