kbuild: allow empty board directories
U-Boot has compelled all boards to have
board/${BOARD}/ or board/${VENDOR}/${BOARD}/ directory.
Sometimes it does not seem suitable for some boards,
for example Sandbox. (Is it a board?)
And arcangel4 board has nothing to compile
under the board directory.
This commit makes the build system more flexible:
If '<none>' is given to the 6th column (=Board name) of boards.cfg,
Kbuild will not descend into the board directory.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/Makefile b/Makefile
index 36de8d4..ecac292 100644
--- a/Makefile
+++ b/Makefile
@@ -636,7 +636,7 @@
libs-$(CONFIG_ARM) += arch/arm/cpu/
libs-$(CONFIG_PPC) += arch/powerpc/cpu/
-libs-y += board/$(BOARDDIR)/
+libs-y += $(if $(BOARDDIR),board/$(BOARDDIR)/)
libs-y := $(sort $(libs-y))