conf: make number of scrollback lines configurable

config.c

@@ -162,6 +162,15 @@ parse_section_main(const char *key, const char *value, struct config *conf,
         conf->render_worker_count = count;
     }
 
+    else if (strcmp(key, "scrollback") == 0) {
+        unsigned long lines;
+        if (!str_to_ulong(value, 10, &lines)) {
+            LOG_ERR("%s:%d: expected an integer: %s", path, lineno, value);
+            return false;
+        }
+        conf->scrollback_lines = lines;
+    }
+
     else {
         LOG_WARN("%s:%u: invalid key: %s", path, lineno, key);
         return false;
@@ -407,6 +416,7 @@ config_load(struct config *conf)
         .term = strdup("foot"),
         .shell = get_shell(),
         .fonts = tll_init(),
+        .scrollback_lines = 1000,
 
         .colors = {
             .fg = default_foreground,

config.h

@@ -11,6 +11,8 @@ struct config {
     char *shell;
     tll(char *) fonts;
 
+    int scrollback_lines;
+
     struct {
         uint32_t fg;
         uint32_t bg;

footrc

@@ -1,6 +1,7 @@
-# term=foot
-# shell=/usr/bin/zsh
 # font=monospace
+# scrollback=1000
+# shell=/usr/bin/zsh
+# term=foot
 # workers=<number of logical CPUs>
 
 [cursor]

main.c

@@ -387,6 +387,7 @@ main(int argc, char *const *argv)
         .alt = {.damage = tll_init(), .scroll_damage = tll_init()},
         .grid = &term.normal,
         .render = {
+            .scrollback_lines = conf.scrollback_lines,
             .workers = {
                 .count = conf.render_worker_count,
                 .queue = tll_init(),

terminal.h

@@ -315,6 +315,7 @@ struct terminal {
 
     struct wayland wl;
     struct {
+        int scrollback_lines;
         struct wl_callback *frame_callback;
 
         struct {