libgflags.a(gflags.cc.o): relocation R_X86_64_32S make pycaffe

gflags is not compiled as a shared library by default; make sure it is compiled as a shared library:

cd gflags/build
cmake .. -DBUILD_SHARED_LIBS=ON
make -j32
sudo make -j32 install

After that glog compiles fine against gflags.