Make sure SIZEOF_CURL_OFF_T is defined before we check for it being > 4.

It is only undefined when this file is included by others (like ares) and
in those cases it doesn't matter.

lib/setup.h

@@ -81,8 +81,15 @@ typedef unsigned char bool;
 #endif
 #endif /* HAVE_LONGLONG */
 
+#ifndef SIZEOF_CURL_OFF_T
+/* If we don't know the size here, we assume a conservative size: 4. When
+   building libcurl, the actual size of this variable should be define in the
+   config*.h file. */
+#define SIZEOF_CURL_OFF_T 4
+#endif
+
 /* We set up our internal prefered (CURL_)FORMAT_OFF_T here */
-#if defined(SIZEOF_CURL_OFF_T) && (SIZEOF_CURL_OFF_T > 4)
+#if SIZEOF_CURL_OFF_T > 4
 #define FORMAT_OFF_T "lld"
 #else
 #define FORMAT_OFF_T "ld"
@@ -273,10 +280,6 @@ typedef struct hostent Curl_addrinfo;
 typedef struct in_addr Curl_ipconnect;
 #endif
 
-#ifndef SIZEOF_CURL_OFF_T
-#define SIZEOF_CURL_OFF_T sizeof(curl_off_t)
-#endif
-
 #ifdef VMS
 #define IOCTL_3_ARGS
 #endif