ncurses 5.7 - patch 20100403

ncurses 5.7 - patch 20100403

+ add configure check for exctags vs ctags, to work around pkgsrc.
+ simplify logic in _nc_get_screensize() to make it easier to see how
  environment variables may override system- and terminfo-values
  (prompted by discussion with Igor Bujna).
+ make debug-traces for COLOR_PAIR and PAIR_NUMBER less verbose.
+ improve handling of color-pairs embedded in attributes for the
  extended-colors configuration.
+ modify MKlib_gen.sh to build link_test with sp-funcs.
+ build-fixes for OpenSolaris aka Solaris 11, for wide-character
  configuration as well as for rpath feature in *-config scripts.