ignore the icc warning 981 "operands are evaluated in unspecified order"

acinclude.m4

@@ -507,13 +507,14 @@ AC_DEFUN([CURL_CC_DEBUG_OPTS],
          dnl this is icc, not gcc.
 
          dnl ICC warnings we ignore:
-         dnl * 279 warns on static conditions in while expressions
          dnl * 269 warns on our "%Od" printf formatters for curl_off_t output:
          dnl   "invalid format string conversion"
+         dnl * 279 warns on static conditions in while expressions
+         dnl * 981 warns on "operands are evaluated in unspecified order"
          dnl * 1419 warns on "external declaration in primary source file"
          dnl   which we know and do on purpose.
 
-         WARN="-wd279,269,1419"
+         WARN="-wd279,269,1419,981"
 
          if test "$gccnum" -gt "600"; then
             dnl icc 6.0 and older doesn't have the -Wall flag