Also test for 'void *' as third arg of accept() (as on Solaris 7 and 8),

Also test for 'void *' as third arg of accept() (as on Solaris 7 and 8),
but take it as 'int *' instead.

Add real test for whether ld -R works on Unixware.

Rename --enable-uniconv to --enable-unicode-conversion.

Install shlibs mode 755 by default, since 644 causes gratuitous complaints
from ldd et al. on some systems.