Revert r360682, as it does not compile on stable/11 (will commit a
minimal indentation fix instead):

Un-MFC r333465 (by lwhsu):

Fix build for platforms using GCC:

• Remove unused or dead store variable
• Remove unused function ctl_copyin_alloc
• Add missing curly brackets, this seems a regression in r287720

Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D15383