Add CI to build ossfuzz fuzzer binaries

scripts/install_libfuzzer.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env sh
+set -e
+TEMPDIR=$(mktemp -d)
+(
+    cd $TEMPDIR
+    svn co https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer libfuzzer
+    mkdir -p build-libfuzzer
+    cd build-libfuzzer
+    CXXFLAGS="-O1 -stdlib=libstdc++"
+    $CXX $CXXFLAGS -std=c++11 -O2 -fPIC -c ../libfuzzer/*.cpp -I../libfuzzer
+    ar r /usr/lib/libFuzzingEngine.a *.o
+)
+rm -rf $TEMPDIR