Suppress unused-variable warnings (treated as errors) in thrift compilation

.travis.yml

@@ -21,7 +21,7 @@ before_install:
 - wget --no-clobber https://github.com/bazelbuild/bazel/releases/download/0.25.1/bazel_0.25.1-linux-x86_64.deb
 - sudo dpkg -i bazel_0.25.1-linux-x86_64.deb
 - sudo apt-get install automake bison flex g++ git libboost-all-dev libevent-dev libssl-dev libtool make pkg-config # thrift dependencies
-- wget http://www.us.apache.org/dist/thrift/0.11.0/thrift-0.11.0.tar.gz && tar -xf thrift-0.11.0.tar.gz && cd thrift-0.11.0/ &&  ./configure --prefix=/usr --with-rs=no --with-ruby=no --with-python=no --with-java=no --with-go=no --with-perl=no --with-php=no --with-csharp=no --with-erlang=no --with-lua=no --with-nodejs=no && make CPPFLAGS=-Wno-unused-variable -j4 && sudo make install && cd -
+- wget http://www.us.apache.org/dist/thrift/0.11.0/thrift-0.11.0.tar.gz && tar -xf thrift-0.11.0.tar.gz && cd thrift-0.11.0/ && CXXFLAGS="-Wno-unused-variable" bash -c './configure --prefix=/usr --with-rs=no --with-ruby=no --with-python=no --with-java=no --with-go=no --with-perl=no --with-php=no --with-csharp=no --with-erlang=no --with-lua=no --with-nodejs=no' && make -sj4 && sudo make install && cd -
 
 install:
 - sudo apt-get install -qq realpath libgflags-dev libprotobuf-dev libprotoc-dev protobuf-compiler libleveldb-dev libgoogle-perftools-dev libboost-dev libssl-dev libevent-dev libboost-test-dev