The size of long is a build time characteristic and as such it is now recorded

in curlbuild.h as CURL_SIZEOF_LONG. Definition now done from configure process
and in CVS curlbuild.h.dist for non-configure systems.

acinclude.m4

@@ -3613,6 +3613,43 @@ _EOF
 ])
 
 
+dnl CURL_CONFIGURE_LONG
+dnl -------------------------------------------------
+dnl Find out the size of long as reported by sizeof() and define
+dnl CURL_SIZEOF_LONG as appropriate to be used in template file
+dnl include/curl/curlbuild.h.in to properly configure the library.
+dnl The size of long is a build time characteristic and as such
+dnl must be recorded in curlbuild.h
+
+AC_DEFUN([CURL_CONFIGURE_LONG], [
+  if test ! -z "$ac_cv_sizeof_long"; then
+    AC_MSG_WARN([AC_CHECK_SIZEOF(long) was called before CURL_CONFIGURE_LONG])
+  fi
+  AC_MSG_CHECKING([size of long])
+  curl_sizeof_long="unknown"
+  for tmp_size in '16' '8' '4' '2' '1' ; do
+    if test "$curl_sizeof_long" = "unknown"; then
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+          typedef char dummy_arr[sizeof(long) == $tmp_size ? 1 : -1];
+        ]],[[
+          dummy_arr[1] = (long)1;
+        ]])
+      ],[
+        curl_sizeof_long="$tmp_size"
+      ])
+    fi
+  done
+  if test "$curl_sizeof_long" = "unknown"; then
+    AC_MSG_ERROR([cannot find out size of long])
+  else
+    AC_MSG_RESULT([$curl_sizeof_long])
+    CURL_DEFINE_UNQUOTED([CURL_SIZEOF_LONG], [$curl_sizeof_long])
+    ac_cv_sizeof_long="$curl_sizeof_long"
+  fi
+])
+
+
 dnl CURL_INCLUDES_INTTYPES
 dnl -------------------------------------------------
 dnl Set up variable with list of headers that must be
@@ -3722,13 +3759,9 @@ AC_DEFUN([CURL_CONFIGURE_CURL_OFF_T], [
     AC_MSG_ERROR([SED not set. Cannot continue without SED being set.])
   fi
   #
-  AC_CHECK_SIZEOF(long)
+  CURL_CONFIGURE_LONG
   AC_CHECK_SIZEOF(void*)
   #
-  if test -z "$ac_cv_sizeof_long" ||
-     test "$ac_cv_sizeof_long" -eq "0"; then
-    AC_MSG_ERROR([cannot find out size of long.])
-  fi
   if test -z "$ac_cv_sizeof_voidp" ||
      test "$ac_cv_sizeof_voidp" -eq "0"; then
     AC_MSG_ERROR([cannot find out size of void*.])