MFC r242465:
Free the dma map -after- it's checked, not before. Or you'll be
potentially referencing already-freed memory.

MFC r242466:
Drop this from 500 to 128, to save a little space on memory constrained
platforms.

Submitted by:	adrian
Obtained from:	Netflix
MFC r251689

Be more agressive about bootstrapping ctfmerge and ctfconvert so
builds from existing releases have a chance of working properly when
WITH_CLANG_IS_CC is enabled.
MFC r249252:
  Remove reference to the nonexistent sysctl node net.inet6.mld.stats.
  Also add cross reference to the icmp6(4).

  PR:	177696