In-memory nested archives

alpha-linuxecoff has compressed archives that are decompressed to a
bfd-in-memory.  We'd need to handle quite a lot of corner cases to
support nesting of such archives, so just stop it before we run into
segfaults later.

	* opncls.c (_bfd_new_bfd_contained_in): Prohibit nested
	archives in memory.
1 file changed