Import lwIP contrib rep

... from http://git.savannah.gnu.org/cgit/lwip/lwip-contrib.git/ into contrib/ subdir, STABLE-2_1_0_RELEASE tag
lwIP contrib is now officially frozen
TODO: Fix build

contrib/ports/unix/example_app/iteropts.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+LOGFILE=iteropts.log
+EXAPPDIR=../../../examples/example_app
+
+pushd `dirname "$0"`
+pwd
+echo Starting Iteropts run >> $LOGFILE
+for f in $EXAPPDIR/test_configs/*.h
+do
+    echo Cleaning...
+    make clean
+    BUILDLOG=$(basename "$f" ".h").log
+    echo testing $f
+    echo testing $f >> $LOGFILE
+    rm $EXAPPDIR/lwipopts_test.h
+    # cat the file to update its timestamp
+    cat $f > $EXAPPDIR/lwipopts_test.h
+    make TESTFLAGS=-DLWIP_OPTTEST_FILE -j 8 &> $BUILDLOG 2>&1 || echo file $f failed >> $LOGFILE
+    echo test $f done >> $LOGFILE
+done
+echo done, cleaning
+make clean
+popd