Required to prevent function-like macros with the same name from
being expanded in the definitions once they become active in a
later C mode. Without the parentheses, the macro would rewrite
the declarator, and the file would consequently fail to compile.
This style is already used for similar cases such as mempcpy().
Reviewed by: fuz
Approved by: fuz (mentor)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D59600
Faraz Vahedi
c389738f21