meta: add internal common library

common/line-source.c

@@ -0,0 +1,12 @@
+#include <ivy/line-source.h>
+
+enum ivy_line_source_status ivy_line_source_readline(
+	struct ivy_line_source *src, char *buf, size_t count, size_t *nr_read,
+	const char *prompt)
+{
+	if (src->s_readline) {
+		return src->s_readline(src, buf, count, nr_read, prompt);
+	}
+
+	return IVY_LS_ERR_NOSYS;
+}