Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

libc: stop exporting cerror

i386 stopped exporting .cerror in r240152, and likewise for amd64 in
r240178. It is not used by other libraries on any platform, so apply
the same change to the remaining architectures.

Reviewed by: jhibbits, jilles
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5774

libc: stop exporting curbrk and minbrk in the private namespace

They are not used anywhere else in the base system and are an internal
implementation detail that does not need to be exposed.

Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5728

Add dl_unwind_find_exidx() for ARM EABI, required for C++ exception
handling. For statically linked apps this uses the __exidx_start/end
symbols set up by the linker. For dynamically linked apps it finds the
shared object that contains the given address and returns the location and
size of the exidx section in that shared object.

The dl_unwind_find_exidx() name is used by other BSD projects and Android,
and is mentioned in clang 3.5 comments as "the BSD interface" for finding
exidx data. GCC (in libgcc_s) expects the exact same API and functionality
to be provided by a function named __gnu_Unwind_Find_exidx(), so we provide
that with an alias ("strong reference").

Reviewed by: kib@
MFC after: 1 week

Export _libc_arm_fpu_present as a private symbol to be used by other
system libraries, for example libm.

Use the compiler-rt version __{u,}divsi3 and __{u,}modsi3 on ARM EABI

Per kib, since __flt_rounds is being added to FreeBSD 10, it
belongs in FBSD_1.3.

MFC after: 1 week

__flt_rounds is a public symbol (expands from the FLT_ROUNDS macro),
so include it in the public namespace on arm just as with
other architectures.

This corrects r236816.

Submitted by: Jan Sieka
MFC after: 1 week

__flt_rounds was omitted from the exported symbols here.

Submitted by: Jan Sieka
Reviewed by: arm@
MFC after: 1 week

Add __aeabi_read_tp to the symbol list.

Replace a proliferation of buggy MD implementations of modf() with a
working MI one. The MI one only needs to be overridden on machines
with non-IEEE754 arithmetic. (The last supported one was the VAX.)
It can also be overridden if someone comes up with a faster one that
actually passes the regression tests -- but this is harder than it sounds.

Unbreak arm build by removing duplicate symbols.

Some libc symbol map cleanups.

net: endhostdnsent is named _endhostdnsent and is
private to netdb family of functions.

posix1e: acl_size.c has been never compiled in,
so there's no "acl_size".

rpc: "getnetid" is a static function.

stdtime: "gtime" is #ifdef'ed out in the source.

some symbols are specific only to some architectures,
e.g., ___tls_get_addr is only defined on i386.

__htonl, __htons, __ntohl and __ntohs are no longer
functions, they are now (internal) defines in
<machine/endian.h>.

Submitted by: ru

Use __mcount() instead of _mcount() to reduce diffs with NetBSD.

Do not export 'end' symbol. It is not meant to be visible to outside
world and it wreak havoc if libc collides with other versioned
libraries.

Remove .mcount from gmon's Symbol map and add it to the appropriate
arch. It can be named differently depending on the arch (.mcount,
_mcount).

Submitted by: marius

Use C comments since we now preprocess these files with CPP.

Add symbol maps and initial symbol version definitions to libc.

Reviewed by: davidxu