Add in the generic makefile from buildroot

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Add PDF to downloader's supported files

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Move some bits out of the Makefile.common.

These should be specified in the real makefile

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Fix downloading a file that's already there

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
SRPM building is optional in configure now

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>