openvdb/python/CMakeLists.txt: Minor fix and CMake v3.11 compatibility (

#259)

Adding the python version string to finding the python module of
Boost fixes this error: CMake Error at /.../FindBoost.cmake:2044

Remove unneeded python version variables as PythonInterp already
defines them.

PYOPENVDB_INSTALL_DIRECTORY variable cannot be set during configure
phase because it is hard set. Test if it is not defined before
setting it to a default.

Signed-off-by: Jonathan Scruggs <[email protected]>

openvdb/python/CMakeLists.txt

@@ -3,7 +3,7 @@ PROJECT ( PyOpenVDB )
 
 FIND_PACKAGE ( PythonInterp REQUIRED )
 FIND_PACKAGE ( PythonLibs REQUIRED )
-FIND_PACKAGE ( Boost ${MINIMUM_BOOST_VERSION} REQUIRED COMPONENTS python )
+FIND_PACKAGE ( Boost ${MINIMUM_BOOST_VERSION} REQUIRED COMPONENTS python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR} )
 
 
 IF ( NOT OPENVDB_BUILD_CORE )
@@ -36,15 +36,10 @@ INCLUDE_DIRECTORIES ( SYSTEM ${BLOSC_INCLUDE_DIR} )
 INCLUDE_DIRECTORIES ( SYSTEM ${TBB_INCLUDE_DIR} )
 INCLUDE_DIRECTORIES ( SYSTEM ${ZLIB_INCLUDE_DIR} )
 INCLUDE_DIRECTORIES ( SYSTEM ${PYTHON_INCLUDE_DIR} )
-# MESSAGE ( "PYTHONLIBS_VERSION_STRING = ${PYTHONLIBS_VERSION_STRING}" )
+# MESSAGE ( "PYTHON_VERSION_STRING = ${PYTHON_VERSION_STRING}" )
 
-STRING(REPLACE "." ";" VERSION_LIST ${PYTHONLIBS_VERSION_STRING})
-LIST(GET VERSION_LIST 0 OPENVDB_PYTHON_VERSION_MAJOR)
-LIST(GET VERSION_LIST 1 OPENVDB_PYTHON_VERSION_MINOR)
-LIST(GET VERSION_LIST 2 OPENVDB_PYTHON_VERSION_PATCH)
-
-# MESSAGE ( "OPENVDB_PYTHON_VERSION_MAJOR = ${OPENVDB_PYTHON_VERSION_MAJOR}" )
-# MESSAGE ( "OPENVDB_PYTHON_VERSION_MINOR = ${OPENVDB_PYTHON_VERSION_MINOR}" )
+# MESSAGE ( "PYTHON_VERSION_MAJOR = ${PYTHON_VERSION_MAJOR}" )
+# MESSAGE ( "PYTHON_VERSION_MINOR = ${PYTHON_VERSION_MINOR}" )
 SET ( OPENVDB_PYTHON_MODULE_SOURCE_FILES
   pyFloatGrid.cc
   pyIntGrid.cc
@@ -54,10 +49,12 @@ SET ( OPENVDB_PYTHON_MODULE_SOURCE_FILES
   pyVec3Grid.cc
   )
 
-SET ( PYOPENVDB_INSTALL_DIRECTORY
-  lib/python${OPENVDB_PYTHON_VERSION_MAJOR}.${OPENVDB_PYTHON_VERSION_MINOR}
-  CACHE STRING "The directory to install the pyopenvdb.so module."
-  )
+IF ( NOT DEFINED PYOPENVDB_INSTALL_DIRECTORY )
+  SET ( PYOPENVDB_INSTALL_DIRECTORY
+    lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}
+    CACHE STRING "The directory to install the pyopenvdb.so module."
+    )
+ENDIF ( NOT DEFINED PYOPENVDB_INSTALL_DIRECTORY )
 
 SET_SOURCE_FILES_PROPERTIES ( ${OPENVDB_PYTHON_MODULE_SOURCE_FILES}
   PROPERTIES