diff --git a/src/main.c b/src/main.c
index bd757a554d637cf630673f45d9d86bb519c29056..fb2f8e20cdf0bc121a9352cca1abb9f10dfd4880 100644
--- a/src/main.c
+++ b/src/main.c
@@ -999,9 +999,8 @@ static int str2num(long *val, char *str)
 static int str2offset(off_t *val, char *str)
 {
 #if SIZEOF_OFF_T > 4
-  /* Ugly, but without going through a bunch of rigamarole,
-   * we don't have the definitions for LLONG_{MIN,MAX} or
-   * LONG_LONG_{MIN,MAX}.
+  /* Ugly, but without going through a bunch of rigmarole, we don't have the
+   * definitions for LLONG_{MIN,MAX} or LONG_LONG_{MIN,MAX}.
    */
 #ifndef LLONG_MAX
 #define LLONG_MAX (off_t)0x7FFFFFFFFFFFFFFFLL
@@ -1012,6 +1011,7 @@ static int str2offset(off_t *val, char *str)
   *val = strtoll(str, NULL, 0);
 #else
   /* TODO:  Handle strtoll stuff...sigh... */
+#error "lack of strtoll() needs fixing"
 #endif
 
   if ((*val == LLONG_MAX || *val == LLONG_MIN) && errno == ERANGE)