[OE-core] About share eglibc work directories

[Robert Yang]

Hi Richard and Saul,

The source code of eglibc and eglibc-nativesdk are not compatible because of
the patch ld-search-order.patch, this makes it a little complex to share their
source directories, what can I think is that always apply
ld-search-order.patch, then in do_configure_prepend:

if sdk && patch_applied:
	do nothing
elif not_sdk && patch_applied:
	un-apply the patch
elif sdk && patch_not_applied:
	apply the patch

I don't know whether there is a CONDITIONAL variable which can make it simple.

And the source of eglibc is 137M, not too large, maybe we would not share them?

-- 
Thanks

Robert