everywhere: make use of new0() and macro() macros, and stop using perror()

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
everywhere: always use O_CLOEXEC where it makes sense

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
Remove unused variable and two function stubs

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
doc: update punctuation

Resolve spotted issues related to missing or extraneous commas, dashes.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
replace tabs with spaces in some files

Files:
* hwdb/60-keyboard.hwdb
* shell-completion/zsh/_systemd-coredumpctl
* src/test/test-helper.h

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
make gcc shut up

If -flto is used then gcc will generate a lot more warnings than before,
among them a number of use-without-initialization warnings. Most of them
without are false positives, but let's make them go away, because it
doesn't really matter.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>