MF projects/building-blocks r275198:

  Use ${.TARGET} instead of hardcoding the name in the dump build rule
Shrink boot2 a bit more by factoring out common pattern
of printf();return(-1);

This shrinks it by 8bytes using clang35 and by 12bytes using clang34.
MFi386: r275237 (by rdivacky)

  Shrink boot2 a bit more by factoring out common pattern
  of printf();return(-1);
Implement --no-fatal-warning for compatibility with newer ld
what ever order the options are passed to ld(1) the --no-fatal-warning always
disable --fatal-warning
MFi386: r275059, r275061, r275062 and r275191 (by rdivacky)

  Shrink boot2 by a couple more bytes.
Ignore more warnings with external gcc
Switch to the ARM unified assembly language as the clang integrated as only
supports it. Binutils supports it when the ".syntax unified" directive
is set.

Sponsored by:	ABT Systems Ltd
Remove lock recursion for the pipe pair mutex, and disable the
recursion on mutex initialization.

The only places where the recursive acquire is performed are read and
write filters, since knlist, which uses the pipe pair mutex as lock,
is locked when filter is called.

The recursion was added in r93296, and consistent locking for
kn_fop->f_event() introduced in r133741.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 month
The current limit of 100k for the linker hints file is getting a bit
crowded as we now are at about 70k. Bump the limit to 1MB instead
which is still quite a reasonable limit and allows for future growth
of this file and possible future expansion to additional data.

MFC After: 2 weeks
Update _ENTRY to use _EENTRY to reduce the common code.
Add support for dtrace:fbt on modules for PowerPC

Summary:
Revert the initial FBT-with-KDB changes for trap_subr*.S, and instead use the
db_trap filter function to handle dtrace trap filtering.  With this, the MMU is
enabled by the support code, simplifying the codepath altogether.

Test Plan: Tested on my G4 PowerBook

Reviewers: #powerpc, nwhitehorn

Reviewed By: nwhitehorn

Differential Revision: https://reviews.freebsd.org/D1207

MFC after:	3 weeks
etc/mail actually applies to MK_SENDMAIL, not MK_MAIL
Revert r275270

MK_MAIL applies to MK_SENDMAIL and a number of other knobs. r275270 incorrectly
applied it to only MK_SENDMAIL
Cross reference tap(4) and tun(4) and include a short explanation as
to how they differ.  This will assist users in selecting which interface
is more appropriate for their purposes.

Approved by:	grog (co-mentor)
MFC after:	2 week
Remove etc/rc.d/mrouted

mrouted has been available in ports for the last 8 years as net/mrouted . An
equivalent rc.d script has been present in the port.

Remove all corresponding variables from etc/defaults/rc.conf

Relnotes: yes
Followup to r275299: add an ObsoleteFiles.inc entry for etc/rc.d/mrouted
Unbreak the code for non-digits below '0' by casting the expression
to unsigned int.

Pointed out by: bde
Make sballoc() and sbfree() functions. Ideally, they could be marked
as static, but unfortunately Infiniband (ab)uses them.

Sponsored by:	Nginx, Inc.
- Move sbcheck() declaration under SOCKBUF_DEBUG.
- Improve SOCKBUF_DEBUG macros.
- Improve sbcheck().

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
Missed in r274421: use sbavail() instead of bare access to sb_cc.