Fix infinite loop in nscd when netgroup is empty (bz #16365)

Currently, when a user looks up a netgroup that does not have any
members, nscd goes into an infinite loop trying to find members in the
group.  This is because it does not handle cases when getnetgrent
returns an NSS_STATUS_NOTFOUND (which is what it does on empty group).
Fixed to handle this in the same way as NSS_STATUS_RETURN, similar to
what getgrent does by itself.
Fix return code from getent netgroup when the netgroup is not found (bz #16366)

nscd incorrectly returns a success even when the netgroup in question
is not found and adds a positive result in the cache.  this patch
fixes this behaviour by adding a negative lookup entry to cache and
returning an error when the netgroup is not found.
Reformat malloc to gnu style.
Fix ldbl-128ibm acoshl inaccuracy (bug 16384).

This patch fixes bug 16384, ldbl-128ibm acoshl inaccuracy, which
showed up while attempting to regenerate ulps for powerpc-nofpu for
2.19.  There were two separate problems, use of __log1p instead of
__log1pl and an insufficiently accurate constant value for log 2
(which this patch replaces by use of M_LN2l), each of which could
cause substantial inaccuracy in affected cases.

Tested for powerpc-nofpu.

	* sysdeps/ieee754/ldbl-128ibm/e_acoshl.c (ln2): Initialize with
	M_LN2l.
	(__ieee754_acoshl): Use __log1pl not __log1p.
Fix ldbl-128ibm asinhl inaccuracy (bug 16385).

This patch fixes bug 16385, ldbl-128ibm asinhl inaccuracy, which
showed up while attempting to regenerate ulps for powerpc-nofpu for
2.19.  The problem here was use of fabs instead of fabsl meaning large
arguments were reduced to the precision of double.  Tested for
powerpc-nofpu.

	* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Use fabsl not
	fabs.
Fix ldbl-128ibm logl inaccuracy (bug 16386).

This patch fixes bug 16386, ldbl-128ibm logl inaccuracy (with
consequent inaccuracy for lgammal) for arguments where the high double
is subnormal, which showed up while attempting to regenerate ulps for
powerpc-nofpu for 2.19.  The problem here is logic failing to allow
for subnormals when calculating the exponent of the argument.  Tested
for powerpc-nofpu.

	* sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): Adjust
	numbers with subnormal high part when calculating exponent.