Pull Kbuild fixes from Masahiro Yamada:
- fix linker script regression caused by dead code elimination support
- fix typos and outdated comments
- specify kselftest-clean as a PHONY target
- fix "make dtbs_install" when $(srctree) includes shell special
characters like '~'
- Move -fshort-wchar to the global option list because defining it
partially emits warnings
* tag 'kbuild-fixes-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: update comments of Makefile.asm-generic
kbuild: Do not use hyphen in exported variable name
Makefile: add kselftest-clean to PHONY target list
Kbuild: use -fshort-wchar globally
fixdep: trivial: typo fix and correction
kbuild: trivial cleanups on the comments
kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured