Enable ASAN on travis

.travis.yml

@@ -36,7 +36,7 @@ before_script:
   - if [ "$SSL_LIB" = "openssl" ]; then ./ci/build_openssl.sh; fi
   # configure ngtcp2
   - autoreconf -i
-  - if [ "$SSL_LIB" = "openssl" ]; then ./configure --enable-werror PKG_CONFIG_PATH=$PWD/../openssl/build/lib/pkgconfig LDFLAGS="-Wl,-rpath,$PWD/openssl/build/lib"; fi
+  - if [ "$SSL_LIB" = "openssl" ]; then ./configure --enable-werror PKG_CONFIG_PATH=$PWD/../openssl/build/lib/pkgconfig CPPFLAGS=-fsanitize=address LDFLAGS="-fsanitize=address -Wl,-rpath,$PWD/openssl/build/lib"; fi
 script:
   # Now build ngtcp2
   - make check