use CURL_SIZEOF_LONG instead of SIZEOF_LONG

That's the symbol we have or generate in include/curl/curlbuild.h

lib/warnless.c

@@ -59,13 +59,13 @@
 #if (CURL_SIZEOF_LONG == 2)
 #  define CURL_MASK_SLONG  0x7FFFL
 #  define CURL_MASK_ULONG  0xFFFFUL
-#elif (SIZEOF_LONG == 4)
+#elif (CURL_SIZEOF_LONG == 4)
 #  define CURL_MASK_SLONG  0x7FFFFFFFL
 #  define CURL_MASK_ULONG  0xFFFFFFFFUL
-#elif (SIZEOF_LONG == 8)
+#elif (CURL_SIZEOF_LONG == 8)
 #  define CURL_MASK_SLONG  0x7FFFFFFFFFFFFFFFL
 #  define CURL_MASK_ULONG  0xFFFFFFFFFFFFFFFFUL
-#elif (SIZEOF_LONG == 16)
+#elif (CURL_SIZEOF_LONG == 16)
 #  define CURL_MASK_SLONG  0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFL
 #  define CURL_MASK_ULONG  0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFUL
 #else