ncurses 5.6 - patch 20080927

ncurses 5.6 - patch 20080927

+ fix build for --with-dmalloc by workaround for redefinition of
  strndup between string.h and dmalloc.h
+ fix build for --disable-sigwinch
+ add environment variable NCURSES_GPM_TERMS to allow override to use
  GPM on terminals other than "linux", etc.
+ disable GPM mouse support when $TERM does not happen to contain
  "linux", since Gpm_Open() no longer limits its assertion to terminals
  that it might handle, e.g., within "screen" in xterm.
+ reset mouse file-descriptor when unloading GPM library (report by
  Miroslav Lichvar).
+ fix build for --disable-leaks --enable-widec --with-termlib
> patch by Juergen Pfeifer:
+ use improved initialization for soft-label keys in Ada95 sample code.
+ discard internal symbol _nc_slk_format (unused since 20080112).
+ move call of slk_paint_info() from _nc_slk_initialize() to
  slk_intern_refresh(), improving initialization.