Skip data type check in DO_CURL_OFF_T_CHECK macro when argument is empty.

CHANGES

@@ -18,6 +18,8 @@ Yang Tse (7 Aug 2008)
   expansion which consists of a single double-quoted string as the result of
   concatenating all of them.
 
+- Skip data type check in DO_CURL_OFF_T_CHECK macro when argument is empty.
+
 - Prevent buildconf from removing 'Makefile' and 'missing' files. This would
   blow away our CVS checked files 'missing' and 'hiper/Makefile'.
 

acinclude.m4

@@ -3579,13 +3579,13 @@ curl_includes_inttypes="\
 ])
 
 
-dnl DO_CURL_OFF_T_CHECK(TYPE, SIZE)
+dnl DO_CURL_OFF_T_CHECK (TYPE, SIZE)
 dnl -------------------------------------------------
 dnl Internal macro for CURL_CONFIGURE_CURL_OFF_T
 
 AC_DEFUN([DO_CURL_OFF_T_CHECK], [
   AC_REQUIRE([CURL_INCLUDES_INTTYPES])dnl
-  if test "$x_typeof" = "unknown"; then
+  if test "$x_typeof" = "unknown" && test ! -z "$1"; then
     tmp_includes=""
     tmp_source=""
     tmp_fmt=""