basic/pager: convert the pager options to a flags argument

Pretty much everything uses just the first argument, and this doesn't make this
common pattern more complicated, but makes it simpler to pass multiple options.

src/sysusers/sysusers.c

@@ -62,7 +62,7 @@ static char *arg_root = NULL;
 static bool arg_cat_config = false;
 static const char *arg_replace = NULL;
 static bool arg_inline = false;
-static bool arg_no_pager = false;
+static PagerFlags arg_pager_flags = 0;
 
 static OrderedHashmap *users = NULL, *groups = NULL;
 static OrderedHashmap *todo_uids = NULL, *todo_gids = NULL;
@@ -1760,7 +1760,7 @@ static int cat_config(void) {
         if (r < 0)
                 return r;
 
-        (void) pager_open(arg_no_pager, false);
+        (void) pager_open(arg_pager_flags);
 
         return cat_files(NULL, files, 0);
 }
@@ -1852,7 +1852,7 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
 
                 case ARG_NO_PAGER:
-                        arg_no_pager = true;
+                        arg_pager_flags |= PAGER_DISABLE;
                         break;
 
                 case '?':