lookat fails to build: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}

[barracuda156]

Fails with gcc-4.2, fails with gcc13:

/opt/local/bin/gcc-mp-13 -DHAVE_CONFIG_H -I.   -I/opt/local/include  -pipe -Os -arch ppc -MT msg.o -MD -MP -MF .deps/msg.Tpo -c -o msg.o msg.c
In file included from ncurses_h.h:26,
                 from input.h:26,
                 from input.c:25:
input.c: In function 'input':
input.c:129:35: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  129 | if (p->insert) mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"I");
      |                                   ^~
input.c:129:47: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  129 | if (p->insert) mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"I");
      |                                               ^~
input.c:130:28: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  130 |    else mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"O");
      |                            ^~
input.c:130:40: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  130 |    else mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"O");
      |                                        ^~
input.c:159:46: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  159 |                           mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"O");
      |                                              ^~
view.c: In function 'view_load':
view.c:181:26: warning: implicit declaration of function 'getdelim' [-Wimplicit-function-declaration]
  181 |      if (p->cmd==2) p->x=getdelim(p->file+p->y_max,&ii,'\n',stdin);
      |                          ^~~~~~~~
input.c:159:58: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  159 |                           mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"O");
      |                                                          ^~
input.c:163:46: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  163 |                           mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"I");
      |                                              ^~
input.c:163:58: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
  163 |                           mvwaddstr(p->w,p->w->_maxy,p->w->_maxx-2,"I");
      |                                                          ^~
make[1]: *** [input.o] Error 1
make[1]: *** Waiting for unfinished jobs....

[barracuda156]

See also: #70242