system.h: Additionally check __LONG_MAX__ for defining curl_off_t

__SIZEOF_LONG__ was introduced in GCC 4.4, __LONG_MAX__ was introduced
in GCC 3.3.

Closes #2216

include/curl/system.h

@@ -348,7 +348,8 @@
    defined(__ppc__) || defined(__powerpc__) || defined(__arm__) ||      \
    defined(__sparc__) || defined(__mips__) || defined(__sh__) ||        \
    defined(__XTENSA__) ||                                               \
-   (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ == 4))
+   (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ == 4)  ||               \
+   (defined(__LONG_MAX__) && __LONG_MAX__ == 2147483647L))
 #    define CURL_TYPEOF_CURL_OFF_T     long long
 #    define CURL_FORMAT_CURL_OFF_T     "lld"
 #    define CURL_FORMAT_CURL_OFF_TU    "llu"
@@ -356,7 +357,8 @@
 #    define CURL_SUFFIX_CURL_OFF_TU    ULL
 #  elif defined(__LP64__) || \
         defined(__x86_64__) || defined(__ppc64__) || defined(__sparc64__) || \
-        (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ == 8)
+        (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ == 8) || \
+        (defined(__LONG_MAX__) && __LONG_MAX__ == 9223372036854775807L)
 #    define CURL_TYPEOF_CURL_OFF_T     long
 #    define CURL_FORMAT_CURL_OFF_T     "ld"
 #    define CURL_FORMAT_CURL_OFF_TU    "lu"