ENH: handle separate python3 variables

CMakeLists.txt

@@ -145,6 +145,9 @@ endif()
 if(NOT OTB_INSTALL_PYTHON_DIR)
   set(OTB_INSTALL_PYTHON_DIR "lib/otb/python")
 endif()
+if(NOT OTB_INSTALL_PYTHON3_DIR)
+  set(OTB_INSTALL_PYTHON3_DIR "lib/otb/python3")
+endif()
 if(NOT OTB_INSTALL_JAVA_DIR)
   set(OTB_INSTALL_JAVA_DIR "lib/otb/java")
 endif()

Modules/Wrappers/SWIG/otb-module-init.cmake

@@ -82,6 +82,9 @@ if ( OTB_WRAP_PYTHON3 )
   swap_cache_variable(NUMPY_INCLUDE_DIR NUMPY_PYTHON3_INCLUDE_DIR)
 
   swap_variable(PYTHON_LIBRARIES PYTHON3_LIBRARIES)
+  swap_variable(NUMPY_INCLUDE_DIRS NUMPY_PYTHON3_INCLUDE_DIRS)
+  swap_variable(NUMPY_FOUND NUMPY_PYTHON3_FOUND)
+  swap_variable(PYTHON_VERSION_STRING PYTHON3_VERSION_STRING)
 
   check_PIC_flag ( Python )
   find_package ( PythonInterp 3 REQUIRED )
@@ -97,6 +100,9 @@ if ( OTB_WRAP_PYTHON3 )
   swap_cache_variable(NUMPY_INCLUDE_DIR NUMPY_PYTHON3_INCLUDE_DIR)
 
   swap_variable(PYTHON_LIBRARIES PYTHON3_LIBRARIES)
+  swap_variable(NUMPY_INCLUDE_DIRS NUMPY_PYTHON3_INCLUDE_DIRS)
+  swap_variable(NUMPY_FOUND NUMPY_PYTHON3_FOUND)
+  swap_variable(PYTHON_VERSION_STRING PYTHON3_VERSION_STRING)
 endif()
 
 #