Add dwarf_loclist to libdw vs. libdwarf check

On CentOS 7 libdw does not include dwarf_loclist but libdwarf
does. This changes adds checking for dwarf_loclist to the check to
determine whether to use libdw instead of libdwarf.

Author: loganbruns

tools/mkport.pl

@@ -326,6 +326,7 @@ sub check_dwarf_h
 void main(int argc, char **argv)
 {
 	dwarf_begin();
+	dwarf_loclist();
 }
 EOF
 	$fh->close();