Enable linknamespace testing for libdl and libcrypt

[Joseph Myers]

On Fri, 18 Nov 2016, Florian Weimer wrote:

> > That is, this configuration involves a namespace bug,
> 
> Agreed.
> 
> > which is  hard to fix so the names in question are whitelisted.
> 
> Sorry, I don't understand this part.

The whitelist in conform/linknamespace.pl covers both false positives and 
genuine but hard-to-fix bugs.  So these names should be added there with 
an appropriate comment.

# The following whitelisted symbols are also allowed for now.
#
# * Bug 17576: stdin, stdout, stderr only reserved with external
# linkage when stdio.h included (and possibly not then), not
# generally.
#
# * Bug 18442: re_syntax_options wrongly brought in by regcomp and
# used by re_comp.
#
# * False positive: matherr only used conditionally.  matherrf/matherrl are used
# by IA64 too for the same reason.
#
@whitelist = qw(stdin stdout stderr re_syntax_options matherr matherrf
                matherrl);

-- 
Joseph S. Myers
joseph@codesourcery.com