BUG/ENH: Fix several issues pointed out.

- Specify the OSX_DEPLOYMENT_TARGET to 10.9.
- Do not link to the actual libpython and instead create a dummy file
  that is used for linking.
- Correctly set the VTK_USE_X flag on APPLE and WIN32.

CMakeLists.txt

@@ -63,7 +63,7 @@ if(VTKPythonPackage_SUPERBUILD)
 
   option(VTK_OPENGL_HAS_OSMESA "Use OSMesa for offscreen rendering" OFF)
   mark_as_advanced(VTK_OPENGL_HAS_OSMESA)
-  if(VTK_OPENGL_HAS_OSMESA)
+  if(VTK_OPENGL_HAS_OSMESA OR APPLE OR WIN32)
     set(VTK_USE_X OFF)
   else()
     set(VTK_USE_X ON)

scripts/macos_build_wheel.py

@@ -4,20 +4,46 @@
 from subprocess import check_call
 import sys
 
-SCRIPT_DIR = os.path.dirname(__file__)
+SCRIPT_DIR = os.path.abspath(os.path.dirname(__file__))
 ROOT_DIR = os.path.abspath(os.path.join(SCRIPT_DIR, ".."))
 STANDALONE_DIR = os.path.join(ROOT_DIR, "standalone-build")
 PROJECT_NAME = "VTK"
 
 
+def get_dummy_python_lib():
+    """Since the python interpreter exports its symbol (see [1]), python modules
+    should not link against any python libraries. To ensure it is not the case,
+    we configure the project using an empty file as python library.
+
+    [1] "Note that libpythonX.Y.so.1 is not on the list of libraries that a
+    manylinux1 extension is allowed to link to. Explicitly linking to
+    libpythonX.Y.so.1 is unnecessary in almost all cases: the way ELF linking
+    works, extension modules that are loaded into the interpreter automatically
+    get access to all of the interpreter's symbols, regardless of whether or
+    not the extension itself is explicitly linked against libpython. [...]"
+
+    Source: https://www.python.org/dev/peps/pep-0513/#libpythonx-y-so-1
+
+    """
+    py_lib = os.path.join(
+        SCRIPT_DIR, 'internal',
+        'libpython-not-needed-symbols-exported-by-interpreter'
+    )
+
+    if not os.path.exists(py_lib):
+        with open(py_lib, 'w') as fp:
+            fp.write('')
+    return py_lib
+
+
 def get_python_info():
     py_exe = sys.executable
     version = sys.version_info[:2]
     py_ver = '{0}.{1}'.format(*version)
     prefix = os.path.abspath(sys.prefix)
     py_inc_dir = glob.glob(os.path.join(prefix, 'include', 'python*'))[0]
     py_lib_dir = os.path.join(prefix, 'lib')
-    py_lib = os.path.join(py_lib_dir, 'libpython%s.dylib' % py_ver)
+    py_lib = get_dummy_python_lib()
     return py_exe, py_ver, py_inc_dir, py_lib
 
 
@@ -26,6 +52,7 @@ def build_wheel(cleanup=False):
     build_type = 'Release'
     source_path = "%s/%s-source" % (STANDALONE_DIR, PROJECT_NAME)
     build_path = "%s/%s-osx_%s" % (ROOT_DIR, PROJECT_NAME, py_ver)
+    osx_target="10.9"
 
     # Clean up previous invocations
     if cleanup and os.path.exists(build_path):
@@ -44,6 +71,7 @@ def build_wheel(cleanup=False):
         "--",
         "-DVTK_SOURCE_DIR:PATH=%s" % source_path,
         "-DVTK_BINARY_DIR:PATH=%s" % build_path,
+        "-DCMAKE_OSX_DEPLOYMENT_TARGET:STRING=%s" % osx_target,
         "-DPYTHON_EXECUTABLE:FILEPATH=%s" % py_exe,
         "-DPYTHON_INCLUDE_DIR:PATH=%s" % py_inc_dir,
         "-DPYTHON_LIBRARY:FILEPATH=%s" % py_lib
@@ -59,4 +87,3 @@ def main():
 
 if __name__ == '__main__':
     main()
-