title: ld error while compiling caffe: libpng and libgfortran not found, shared libraries
body: <p>I'm trying to compile caffe on ubuntu 14.04 LTS with Anaconda, in CPU-only mode and with OpenBLAS. Unfortunately, I get an ld error.</p>
  
  <p>I followed the instructions, added the dependencies that didn't come with Anaconda and adjusted the Makefile.config accordingly, especially included the Anaconda path.
  When I do <code>make all</code> I get the error you see below (I also included the Makefile.config), even though the two files that were not found are in the anaconda/lib folder and in their respective pkgs folders as shared libraries.</p>
  
  <p>Thank you very much for your help!</p>
  
  <p>Terminal:</p>
  
  <pre><code>CXX/LD -o .build_release/tools/extract_features.bin
  /usr/bin/ld: warning: libpng15.so.15, needed by /home/mclab/anaconda/lib/libopencv_highgui.so, not found (try using -rpath or -rpath-link)
  /usr/bin/ld: warning: libgfortran.so.1, needed by /home/mclab/anaconda/lib/libopenblas.so, not found (try using -rpath or -rpath-link)
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_strip_alpha@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_get_io_ptr@PNG15_0'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_pow_i4_i4'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_palette_to_rgb@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_swap@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_write_end@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_compression_level@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_write_image@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_destroy_read_struct@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_write_info@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_gray_to_rgb@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_destroy_write_struct@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_get_IHDR@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_read_update_info@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_compression_strategy@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_create_read_struct@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_read_info@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_longjmp_fn@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_read_image@PNG15_0'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_compare_string'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_create_write_struct@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_bgr@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_create_info_struct@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_write_fn@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_init_io@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_packing@PNG15_0'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_pow_r8_i4'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_concat_string'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_pow_r4_i4'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_etime'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_error@PNG15_0'
  /home/mclab/anaconda/lib/libopenblas.so: undefined reference to `_gfortran_copy_string'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_strip_16@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_read_end@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_IHDR@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_read_fn@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_expand_gray_1_2_4_to_8@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_rgb_to_gray@PNG15_0'
  /home/mclab/anaconda/lib/libopencv_highgui.so: undefined reference to `png_set_filter@PNG15_0'
  collect2: error: ld returned 1 exit status
  make: *** [.build_release/tools/extract_features.bin] Error 1
  </code></pre>
  
  <p>Makefile.config:</p>
  
  <pre><code>## Refer to http://caffe.berkeleyvision.org/installation.html
  # Contributions simplifying and improving our build system are welcome!
  
  # cuDNN acceleration switch (uncomment to build with cuDNN).
  # USE_CUDNN := 1
  
  # CPU-only switch (uncomment to build without GPU support).
   CPU_ONLY := 1
  
  # To customize your choice of compiler, uncomment and set the following.
  # N.B. the default for Linux is g++ and the default for OSX is clang++
   CUSTOM_CXX := g++
  
  # CUDA directory contains bin/ and lib/ directories that we need.
  CUDA_DIR := /usr/local/cuda
  # On Ubuntu 14.04, if cuda tools are installed via
  # "sudo apt-get install nvidia-cuda-toolkit" then use this instead:
  # CUDA_DIR := /usr
  
  # CUDA architecture setting: going with all of them.
  # For CUDA &lt; 6.0, comment the *_50 lines for compatibility.
  CUDA_ARCH := -gencode arch=compute_20,code=sm_20 \
          -gencode arch=compute_20,code=sm_21 \
          -gencode arch=compute_30,code=sm_30 \
          -gencode arch=compute_35,code=sm_35 \
          -gencode arch=compute_50,code=sm_50 \
          -gencode arch=compute_50,code=compute_50
  
  # BLAS choice:
  # atlas for ATLAS (default)
  # mkl for MKL
  # open for OpenBlas
  BLAS := open
  # Custom (MKL/ATLAS/OpenBLAS) include and lib directories.
  # Leave commented to accept the defaults for your choice of BLAS
  # (which should work)!
   BLAS_INCLUDE := /home/mclab/anaconda/pkgs/openblas-0.2.14-1/include
   BLAS_LIB := /home/mclab/anaconda/pkgs/openblas-0.2.14-1/lib
  
  # Homebrew puts openblas in a directory that is not on the standard search path
  # BLAS_INCLUDE := $(shell brew --prefix openblas)/include
  # BLAS_LIB := $(shell brew --prefix openblas)/lib
  
  # This is required only if you will compile the matlab interface.
  # MATLAB directory should contain the mex binary in /bin.
  # MATLAB_DIR := /usr/local
  # MATLAB_DIR := /Applications/MATLAB_R2012b.app
  
  # NOTE: this is required only if you will compile the python interface.
  # We need to be able to find Python.h and numpy/arrayobject.h.
  PYTHON_INCLUDE := /home/mclab/anaconda/include/python2.7 \
          /home/mclab/anaconda/lib/python2.7/site-packages/numpy/core/include
  # Anaconda Python distribution is quite popular. Include path:
  # Verify anaconda location, sometimes it's in root.
  # ORIGINAL:
   ANACONDA_HOME := $(HOME)/anaconda
   PYTHON_INCLUDE := $(ANACONDA_HOME)/include \
           $(ANACONDA_HOME)/include/python2.7 \
           $(ANACONDA_HOME)/lib/python2.7/site-packages/numpy/core/include \
  # MODIFIED
  # ANACONDA_HOME := /home/mclab/anaconda
  # PYTHON_INCLUDE := /home/mclab/anaconda/include \
  #        /home/mclab/anaconda/include/python2.7 \
  #        /home/mclab/anaconda/lib/python2.7/site-packages/numpy/core/include \
  
  # We need to be able to find libpythonX.X.so or .dylib.
  # PYTHON_LIB := /usr/lib
   PYTHON_LIB := $(ANACONDA_HOME)/lib
  
  # Homebrew installs numpy in a non standard path (keg only)
  # PYTHON_INCLUDE += $(dir $(shell python -c 'import numpy.core; print(numpy.core.__file__)'))/include
  # PYTHON_LIB += $(shell brew --prefix numpy)/lib
  
  # Uncomment to support layers written in Python (will link against Python libs)
   WITH_PYTHON_LAYER := 1
  
  # Whatever else you find you need goes here.
  INCLUDE_DIRS := $(PYTHON_INCLUDE) /usr/local/include
  LIBRARY_DIRS := $(PYTHON_LIB) /usr/local/lib /usr/lib
  
  # If Homebrew is installed at a non standard location (for example your home directory) and you use it for general dependencies
  # INCLUDE_DIRS += $(shell brew --prefix)/include
  # LIBRARY_DIRS += $(shell brew --prefix)/lib
  
  # Uncomment to use `pkg-config` to specify OpenCV library paths.
  # (Usually not necessary -- OpenCV libraries are normally installed in one of the above $LIBRARY_DIRS.)
  # USE_PKG_CONFIG := 1
  
  BUILD_DIR := build
  DISTRIBUTE_DIR := distribute
  
  # Uncomment for debugging. Does not work on OSX due to https://github.com/BVLC/caffe/issues/171
  # DEBUG := 1
  
  # The ID of the GPU that 'make runtest' will use to run unit tests.
  TEST_GPUID := 0
  
  # enable pretty build (comment to see full commands)
  Q ?= @
  </code></pre>