kbuild: fix 'make modules' error when CONFIG_DEBUG_INFO_BTF_MODULES=y
[ Upstream commit
74d3320f6f7cf72de88a7e8df573821f6db90239 ]
When CONFIG_DEBUG_INFO_BTF_MODULES=y, running 'make modules'
in the clean kernel tree will get the following error.
$ grep CONFIG_DEBUG_INFO_BTF_MODULES .config
CONFIG_DEBUG_INFO_BTF_MODULES=y
$ make -s clean
$ make modules
[snip]
AR vmlinux.a
ar: ./built-in.a: No such file or directory
make: *** [Makefile:1241: vmlinux.a] Error 1
'modules' depends on 'vmlinux', but builtin objects are not built.
Define KBUILD_BUILTIN.
Fixes: f73edc8951b2 ("kbuild: unify two modpost invocations")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>