makefile recompile with -fPIC - linux

Question

So, I'm trying to build something in make. I produced the files via cmake, went to the appropriate folder for the build file, and:
make
Scanning dependencies of target Spenvis
[ 33%] Building CXX object source/CMakeFiles/Spenvis.dir/pySpenvisCSV.cc.o
[ 66%] Building CXX object source/CMakeFiles/Spenvis.dir/SpenvisCSV.cc.o
[100%] Building CXX object source/CMakeFiles/Spenvis.dir/SpenvisCSVCollection.cc.o
Linking CXX shared library libSpenvis.so
/usr/bin/ld: /usr/local/lib64/libpython2.7.a(abstract.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib64/libpython2.7.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
make[2]: *** [source/libSpenvis.so] Error 1
make[1]: *** [source/CMakeFiles/Spenvis.dir/all] Error 2
make: *** [all] Error 2
I'm a bit of a novice as far as make/cmake goes. I'm uncertain where to go from here. I've looked at several suggestions, but I'm uncertain which are relevant to my particular problem and how to implement the suggested fixes in the first place.
Halp!
There are two CMakeLists.txt files within the python_utilities directory. I'll include both. One from spenvis_csv/source:
# Make sure the compiler can find include files
include_directories (${PYSPENVIS_SOURCE_DIR})
# get boost
set(Boost_USE_STATIC_LIBS OFF)
#set(Boost_USE_MULTIEADED ON)
find_package(Boost COMPONENTS
python
REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})
link_directories(${Boost_LIBRARY_DIRS})
# get python
include(FindPythonLibs)
set(PythonLibs_USE_STATIC_LIBS OFF)
find_package(PythonLibs REQUIRED)
include_directories(${PYTHON_INCLUDE_DIRS})
link_directories(${PYTHON_LIBRARIES})
#
add_library(Spenvis SHARED pySpenvisCSV.cc SpenvisCSV.cc SpenvisCSVCollection.cc)
TARGET_LINK_LIBRARIES(Spenvis ${Boost_LIBRARIES} ${PYTHON_LIBRARIES})
And then the second much shorter one:
cmake_minimum_required (VERSION 2.6)
set (Boost_NO_BOOST_CMAKE=ON)
project (PYSPENVIS)
add_subdirectory ("source")

Answer 1

You are linking against the static python library which, I believe, is typically not going to be built with -fPIC so it's code won't be relocatable. Your Spenvis target, on the other hand, is a shared library and will be built with -fPIC, but linking in non-PIC code isn't going to work like this. This is what the linker is saying to you.
If it is possible, can you link against the shared version of the python library (i.e. libpython.so.2.7 or something similar, depending on how your system names it)? I would have expected CMake to prefer linking to the shared library by default, so I'm wondering if either:
You are missing the shared libpython library on your system (unlikely, but possible).
You've included some CMake options which tell it to prefer linking in static libraries.
You've explicitly given CMake the static python library to link in somehow.
If you are using the FindPythonLibs CMake module, I would have expected that to be giving you the shared python library in the PYTHON_LIBRARIES variable, if it is available on your system. If you update your question to include your CMakeLists.txt file, that may help identify the problem.