FreeBSD_HEAD_i386 - Build #1580 - Fixed

FreeBSD_HEAD_i386 - Build #1580 - Fixed:

Build information: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/1580/
Full change log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/1580/changes
Full build log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/1580/console

Change summaries:

290334 by ae:
Eliminate any conditional increments of object_opcodes in the
check_ipfw_rule_body() function. This function is intended to just
determine that rule has some opcodes that can be rewrited. Then the
ref_rule_objects() function will determine real number of rewritten
opcodes using classify callback.

Reviewed by:	melifaro
Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC

290332 by ae:
Add ipfw_check_object_name_generic() function to do basic checks for an
object name correctness. Each type of object can do more strict checking
in own implementation. Do such checks for tables in check_table_name().

Reviewed by:	melifaro
Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC

290330 by ae:
Implement `ipfw internal olist` command to list named objects.

Reviewed by:	melifaro
Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC

290329 by ache:
Use meaningful errno for ssize_t overflow in read().
Catch size_t overflow in malloc().

PR:     204230
MFC after:      1 week

290328 by hselasky:
Revert r290327. The compiler warnings seems to be specific to clang v3.5 only.