CMake: fix AUDASPACE disabling WITH_PYTHON for Blender

When AUDASPACE couldn't find NUMPY, it would disable WITH_PYTHON for
the rest of Blender. Now setting the value globally is only done for
standalone AUDASPACE builds. Now it's possible to build Blender with
AUDASPACE & PYTHON but without NUMPY.

While this isn't an especially important configuration to support,
having Python mysteriously disabled is a hassle to troubleshoot.

NOTE: extern/audaspace/CMakeLists.txt has become out sync with the
original [0], it seems this is being maintained in our repository.

[0]: https://github.com/neXyon/audaspace/blob/master/CMakeLists.txt

intern/audaspace/CMakeLists.txt

@@ -35,11 +35,15 @@ if(NOT WITH_SYSTEM_AUDASPACE)
 else()
   list(APPEND LIB
     ${AUDASPACE_C_LIBRARIES}
-    ${AUDASPACE_PY_LIBRARIES}
   )
+  if(WITH_PYTHON AND WITH_PYTHON_NUMPY)
+    list(APPEND LIB
+      ${AUDASPACE_PY_LIBRARIES}
+    )
+  endif()
 endif()
 
-if(WITH_PYTHON)
+if(WITH_PYTHON AND WITH_PYTHON_NUMPY)
   list(APPEND INC_SYS
     ${PYTHON_INCLUDE_DIRS}
   )