kbuild: fix single target builds for external modules

Commit f566e1fbadb6 ("kbuild: make multiple directory targets work")
broke single target builds for external modules. Fix this.

Fixes: f566e1fbadb6 ("kbuild: make multiple directory targets work")
Reported-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Bjørn Mork <bjorn@mork.no>

Changed files
+1 -1
+1 -1
Makefile
··· 1754 1754 descend: $(build-dirs) 1755 1755 $(build-dirs): prepare 1756 1756 $(Q)$(MAKE) $(build)=$@ \ 1757 - single-build=$(if $(filter-out $@/, $(filter $@/%, $(single-no-ko))),1) \ 1757 + single-build=$(if $(filter-out $@/, $(filter $@/%, $(KBUILD_SINGLE_TARGETS))),1) \ 1758 1758 need-builtin=1 need-modorder=1 1759 1759 1760 1760 clean-dirs := $(addprefix _clean_, $(clean-dirs))