diff --git a/lib/setup.h b/lib/setup.h
index 4268b9bf6a..c1f7135e54 100644
--- a/lib/setup.h
+++ b/lib/setup.h
@@ -323,7 +323,8 @@
 #    if defined(_LP64) || defined(_LARGE_FILES)
 #      define SIZEOF_OFF_T 8
 #    endif
-#  else
+#  endif
+#  ifndef SIZEOF_OFF_T
 #    define SIZEOF_OFF_T 4
 #  endif
 #endif
diff --git a/src/main.c b/src/main.c
index 62c34cbdfb..784d1750fd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -263,7 +263,8 @@ typedef enum {
 #    if defined(_LP64) || defined(_LARGE_FILES)
 #      define SIZEOF_OFF_T 8
 #    endif
-#  else
+#  endif
+#  ifndef SIZEOF_OFF_T
 #    define SIZEOF_OFF_T 4
 #  endif
 #endif