Restore accidentally removed content.
Merge topic 'add_definitions-no-genex' into next

27ae1fee Restore accidentally removed content.
Revert "Restore accidentally removed content."

This reverts commit 27ae1fee7ab2910a76973bcf98bd494d745d208a.
Restore docs.
Merge topic 'add_definitions-no-genex' into next

2129c8e9 Restore docs.
eb10d9f5 Revert "Restore accidentally removed content."
add_definitions: Don't document genex support.

This command does not support generator expressions. The documentation
was mistakenly extended to claim it in commit v3.0.0-rc1~60^2~3 (Help: Mark
up the buildsystem commands documentation, 2014-02-03).
Merge topic 'add_definitions-no-genex' into next

3447b417 add_definitions: Don't document genex support.