--- CMakeLists.txt.orig	2020-08-27 11:28:26 UTC
+++ CMakeLists.txt
@@ -154,6 +154,7 @@ IF(WITH_CORE)
     # as otherwise user has to use PYTHONPATH environment variable to add
     # QGIS bindings to package search path
     SET (BINDINGS_GLOBAL_INSTALL FALSE CACHE BOOL "Install bindings to global python directory? (might need root)")
+    SET (SIP_GLOBAL_INSTALL FALSE CACHE BOOL "Install sip source files to system sip directory? (might need root)")
     SET (WITH_STAGED_PLUGINS TRUE CACHE BOOL "Stage-install core Python plugins to run from build directory? (utilities and console are always staged)")
     SET (WITH_PY_COMPILE FALSE CACHE BOOL "Determines whether Python modules in staged or installed locations are byte-compiled")
     # concatenate QScintilla2 API files
@@ -851,7 +852,7 @@ IF (WITH_CORE AND WITH_BINDINGS)
   INCLUDE(SIPMacros)
 
   SET(SIP_INCLUDES ${PYQT_SIP_DIR} ${CMAKE_SOURCE_DIR}/python)
-  SET(SIP_CONCAT_PARTS 4)
+  SET(SIP_CONCAT_PARTS 6)
 
   IF (NOT BINDINGS_GLOBAL_INSTALL)
     SET(PYTHON_SITE_PACKAGES_DIR ${QGIS_DATA_DIR}/python)