Rewrite Python library finding

Should fix building with Python 3 on Mac OS X.

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8.3)
+cmake_minimum_required(VERSION 2.8.8)
 
 project(cpsm)
 option(PY3 "Build for python3 instead of python2." OFF)
@@ -28,12 +28,12 @@ endif()
 if(PY3)
     set(Python_ADDITIONAL_VERSIONS 3.5 3.4 3.3)
     find_package(PythonInterp 3 REQUIRED)
-    find_package(PythonLibs 3 REQUIRED)
 else()
     set(Python_ADDITIONAL_VERSIONS 2.7 2.6)
-    find_package(PythonLibrary REQUIRED)
+    find_package(PythonInterp REQUIRED)
 endif()
-include_directories(${PYTHON_INCLUDE_PATH})
+find_package(PythonLibsCustom REQUIRED)
+include_directories(${PYTHON_INCLUDE_DIRS})
 
 find_package(Threads REQUIRED)
 

cmake/FindPythonLibsCustom.cmake

@@ -0,0 +1,46 @@
+# FindPythonLibsCustom
+# --------------------
+#
+# This module locates Python libraries.
+#
+# This code sets the non-deprecated subset of the variables set by CMake's
+# built-in FindPythonLibs:
+#
+# PYTHONLIBS_FOUND - have the Python libs been found
+# PYTHON_LIBRARIES - path to the Python library
+# PYTHON_INCLUDE_DIRS - path to where Python.h is found
+# PYTHONLIBS_VERSION_STRING - version of the Python libs found
+#
+# If calling both `find_package(PythonInterp)` and
+# `find_package(PythonLibsCustom)`, call `find_package(PythonInterp)` first.
+#
+# Compatibility: Believed to be CMake >=2.8.8 (earlier versions of
+# FindPythonLibs do not provide PYTHONLIBS_VERSION_STRING).
+
+include(FindPackageHandleStandardArgs)
+
+find_package(PythonInterp)
+if(PYTHONINTERP_FOUND)
+  find_file(_Python_pyinfo_py pyinfo.py PATHS ${CMAKE_MODULE_PATH})
+  if(_Python_pyinfo_py)
+    execute_process(COMMAND ${PYTHON_EXECUTABLE} ${_Python_pyinfo_py} OUTPUT_VARIABLE _Python_pyinfo)
+    unset(_Python_pyinfo_py)
+    if(_Python_pyinfo)
+      string(REGEX REPLACE "^.*\ninc_dir:([^\n]*)\n.*$" "\\1" PYTHON_INCLUDE_DIRS ${_Python_pyinfo})
+      string(REGEX REPLACE "^.*\nlib_name:([^\n]*)\n.*$" "\\1" _Python_lib_name ${_Python_pyinfo})
+      string(REGEX REPLACE "^.*\nlib_ver:([^\n]*)\n.*$" "\\1" PYTHONLIBS_VERSION_STRING ${_Python_pyinfo})
+      string(REGEX REPLACE "^.*\nlib_dir:([^\n]*)\n.*$" "\\1" _Python_lib_dir ${_Python_pyinfo})
+      unset(_Python_pyinfo)
+      find_library(PYTHON_LIBRARIES NAMES ${_Python_lib_name} HINTS ${_Python_lib_dir})
+      unset(_Python_lib_name)
+      unset(_Python_lib_dir)
+    endif(_Python_pyinfo)
+  else(_Python_pyinfo_py)
+    message(SEND_ERROR "failed to find pyinfo.py")
+  endif(_Python_pyinfo_py)
+  FIND_PACKAGE_HANDLE_STANDARD_ARGS(PythonLibs DEFAULT_MSG PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS PYTHONLIBS_VERSION_STRING)
+else(PYTHONINTERP_FOUND)
+  message(STATUS "Python interpreter not found, falling back to FindPythonLibs")
+  find_package(PythonLibs)
+endif(PYTHONINTERP_FOUND)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(PythonLibsCustom DEFAULT_MSG PYTHONLIBS_FOUND)

cmake/pyinfo.py

@@ -0,0 +1,21 @@
+from __future__ import print_function
+
+from distutils import sysconfig
+
+if __name__ == "__main__":
+    print()
+    print("inc_dir:%s" % sysconfig.get_python_inc())
+    # From testing, these interpretations of LIBRARY and LIBPL are valid for
+    # both Python 2.7 and Python 3.5 on both Ubuntu and Mac OS X (with Homebrew
+    # Python).
+    lib_name = sysconfig.get_config_var("LIBRARY")
+    if lib_name.startswith("lib"):
+        lib_name = lib_name[3:]
+    if lib_name.endswith(".a"):
+        lib_name = lib_name[:-2]
+    print("lib_name:%s" % lib_name)
+    lib_ver = lib_name
+    if lib_ver.startswith("python"):
+        lib_ver = lib_ver[6:]
+    print("lib_ver:%s" % lib_ver)
+    print("lib_dir:%s" % sysconfig.get_config_var("LIBPL"))