-# Call a source code checker (by default, "sparse") as part of the
-# C compilation.
-#
-# Use 'make C=1' to enable checking of only re-compiled files.
-# Use 'make C=2' to enable checking of *all* source files, regardless
-# of whether they are re-compiled or not.
-#
-# See the file "Documentation/dev-tools/sparse.rst" for more details,
-# including where to get the "sparse" utility.
-
-ifeq ("$(origin C)", "command line")
- KBUILD_CHECKSRC = $(C)
-endif
-ifndef KBUILD_CHECKSRC
- KBUILD_CHECKSRC = 0
-endif
-
-# Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
-# directory of external module to build. Setting M= takes precedence.
-ifeq ("$(origin M)", "command line")
- KBUILD_EXTMOD := $(M)
-endif
-
-$(if $(word 2, $(KBUILD_EXTMOD)), \
- $(error building multiple external modules is not supported))
-
-export KBUILD_CHECKSRC KBUILD_EXTMOD
-
-extmod-prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)
-