Fix ldbl-128 cos range reduction near pi/2 (bug 15429).
Fix ldbl-128ibm cos range reduction near pi/2 (bug 15359).
Add more comments to dlclose() algorithm.

The algorithm for scanning dependencies upon dlclose is
less than immediately obvious. This patch adds two bits
of comments that explain why you start the dependency
search at l_initfini[1], and why you need to restart
the search.

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2013-05-09  Carlos O'Donell  <carlos@redhat.com>

	* elf/dl-close.c (_dl_close_worker): Add comments.