Add all handled signals to ppoll() set

This addresses an issue where callers of notcurses_getc_blocking()
wouldn't exit on SIGINT etc. until another keystroke was received.
The exit is now immediate, and the proper exit code is propagated.

src/lib/input.c

@@ -3,13 +3,17 @@
 
 sig_atomic_t resize_seen = 0;
 
+// add the keypress we just read to our input queue (assuming there is room).
+// if there is a full UTF8 codepoint or keystroke (composed or otherwise),
+// return it, and pop it from the queue.
 static int
 handle_getc(const notcurses* nc __attribute__ ((unused)), cell* c, int kpress,
             ncspecial_key* special){
-// fprintf(stderr, "KEYPRESS: %d\n", kpress);
+fprintf(stderr, "KEYPRESS: %d\n", kpress);
   if(kpress < 0){
     return -1;
   }
+  // FIXME add it to the queue, then consult queue
   *special = 0;
   if(kpress == 0x04){ // ctrl-d
     return -1;
@@ -30,6 +34,7 @@ int notcurses_getc(const notcurses* nc, cell* c, ncspecial_key* special){
     *special = NCKEY_RESIZE;
     return 1;
   }
+  // FIXME check queue
   int r = getc(nc->ttyinfp);
   if(r < 0){
     return r;
@@ -49,15 +54,18 @@ int notcurses_getc_blocking(const notcurses* nc, cell* c, ncspecial_key* special
   sigset_t smask;
   sigfillset(&smask);
   sigdelset(&smask, SIGWINCH);
+  sigdelset(&smask, SIGINT);
+  sigdelset(&smask, SIGQUIT);
+  sigdelset(&smask, SIGSEGV);
   while((pret = ppoll(&pfd, 1, NULL, &smask)) >= 0){
     if(pret == 0){
       continue;
     }
-    r = getc(nc->ttyinfp);
+    r = notcurses_getc(nc, c, special);
     if(r < 0){
       break; // want EINTR handling below
     }
-    return handle_getc(nc, c, r, special);
+    return r;
   }
   if(errno == EINTR){
     if(resize_seen){