* support/regression/tests/structflexarray.c: flexible array members

  not supported by gcc < 3
* lib/variables.mk, lib/fetch.mk, sdcc-build-bootstrap.sh:
  use common ORIG tree with VPATH functionality

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4238 4a8a32a2-be11-0410-ad9d-d568d2c75423