Make an attempt at fixing our current Solaris 11 breakage: add a configure

probe for opterr (exactly like the one for optreset) and have getopt.c
define the variables only if configure doesn't find them in libc.

configure

@@ -18655,6 +18655,65 @@ fi
 fi
 
 
+{ echo "$as_me:$LINENO: checking for opterr" >&5
+echo $ECHO_N "checking for opterr... $ECHO_C" >&6; }
+if test "${pgac_cv_var_int_opterr+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <unistd.h>
+int
+main ()
+{
+extern int opterr; opterr = 1;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+  pgac_cv_var_int_opterr=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	pgac_cv_var_int_opterr=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+{ echo "$as_me:$LINENO: result: $pgac_cv_var_int_opterr" >&5
+echo "${ECHO_T}$pgac_cv_var_int_opterr" >&6; }
+if test x"$pgac_cv_var_int_opterr" = x"yes"; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_INT_OPTERR 1
+_ACEOF
+
+fi
+
 { echo "$as_me:$LINENO: checking for optreset" >&5
 echo $ECHO_N "checking for optreset... $ECHO_C" >&6; }
 if test "${pgac_cv_var_int_optreset+set}" = set; then