See https://debbugs.gnu.org/cgi/bugreport.cgi?bug=73835

diff -upr guile-3.0.9.orig/libguile/filesys.c guile-3.0.9/libguile/filesys.c
--- guile-3.0.9.orig/libguile/filesys.c	2024-10-16 19:35:32.891699878 +0200
+++ guile-3.0.9/libguile/filesys.c	2024-10-16 19:43:31.660093415 +0200
@@ -1329,7 +1329,7 @@ SCM_DEFINE (scm_sendfile, "sendfile", 3,
 
   ssize_t result SCM_UNUSED;
   size_t c_count, total = 0;
-  scm_t_off c_offset;
+  off_t c_offset;
   int in_fd, out_fd;
 
   VALIDATE_FD_OR_PORT (out_fd, out, 1);
