kbuild: make samples really depend on headers_install
Kernel headers must be installed into $(objtree)/usr/include to avoid
the build failure of samples.
Commit ddea05fa148b ("kbuild: make samples depend on headers_install")
addressed this, but "samples/" is only used for the single target build.
"make samples/" properly installs kernel headers, but it does not work
for general building because a phony target "sample" (no trailing slash)
is used.
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: David Howells <dhowells@redhat.com>
Masahiro Yamada