Use $target_cpu instead of `arch`

We should not be using arch for a few reasons.  First off it might
not be installed on their system, and secondly they may be trying
to cross-compile.

Check sourcelink is set before passing to readlink

When no source was found in any of the expected paths treat
this as fatal and provide the user with a hint as to what
they should do.

Only make compiler warnings fatal with --enable-debug

While in theory I like the idea of compiler warnings always being
fatal.  In practice this causes problems when small harmless errors
cause build failures for end users.  To handle this I've updated
the build system such that -Werror is only used when --enable-debug
is passed to configure.  This is how I always build when developing
so I'll catch all build warnings and end users will not get stuck
by minor issues.

Merge commit 'refs/top-bases/zfs-branch' into zfs-branch

Merge branch 'gcc-branch' into refs/top-bases/zfs-branch

Merge commit 'refs/top-bases/gcc-branch' into gcc-branch

Merge branch 'gcc-fortify-source' into refs/top-bases/gcc-branch

Fix -Werror=format-security compiler option

Noticed under Ubuntu kernel builds, there were two instances where
printf() was not called with a "%s" and instread directly printed
the string.  This can potentially result in a crash and is considered
bad form by gcc.  It has been fixed by adding the needed "%s".

Allow config/build to work with autoconf-2.65

As of autoconf-2.65 the AC_LANG_SOURCE source macro no longer
includes the confdef.h results when expanded.  To handle this
simply explicitly include confdef.h in conftest.c.  This will
cause two copies to of confdef.h to be added to the test for
earlier autoconf versions but this is not harmful.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

Linux-2.6.33 compat, check <generated/utsrelease.h> for UTS_RELEASE

It seems the upstream community moved the definition of UTS_RELEASE
yet again as of linux-2.6.33.  Update the build system to check in
all three possible locations where your kernel version may be defined.

    $kernelbuild/include/linux/version.h
    $kernelbuild/include/linux/utsrelease.h
    $kernelbuild/include/generated/utsrelease.h

Merge commit 'refs/top-bases/zfs-branch' into zfs-branch

Merge branch 'gcc-branch' into refs/top-bases/zfs-branch

Merge commit 'refs/top-bases/gcc-branch' into gcc-branch

Merge branch 'gcc-fortify-source' into refs/top-bases/gcc-branch

Update zfs.spec.in to reference updated README.markdown file

The spec file references the README by the previous name which
has changed to make it github friendly.  This results in an
rpm build failure.

Use VERIFY() for asprintf due to rpm -D_FORTIFY_SOURCE=2

This check is part of ztest and a memory failure here is unlikely.
However, if this does occur simply exiting is an perfectly valid
way to handle the issue and it resulves the compiler warning.

        ztest.c:5522: error: ignoring return value of 'asprintf',
        declared with attribute warn_unused_result

Merge branch 'fix-branch' into refs/top-bases/zfs-branch

Merge commit 'refs/top-bases/zfs-branch' into zfs-branch

Merge commit 'refs/top-bases/fix-branch' into fix-branch

Merge branch 'fix-stack-traverse_visitbp' into refs/top-bases/fix-branch

Add configure check for -Wframe-larger-than=<size>

It turns out the gcc option -Wframe-larger-than=<size> which I recently
added to the build system is not supported in older versions of gcc.
Since this is just a flag to ensure I keep stack usage under control
I've added a configure check to detect if gcc supports it.  If it's
available we use it in the proper places, if it's not we don't.

Minor fix to ensure tv_depth is there when debugging is disabled.

Merge commit 'refs/top-bases/zfs-branch' into zfs-branch

Merge branch 'fix-branch' into refs/top-bases/zfs-branch

Merge commit 'refs/top-bases/fix-branch' into fix-branch

Merge branch 'fix-stack-ztest' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-ztest' into fix-stack-ztest

Merge commit 'refs/top-bases/fix-pthreads' into fix-pthreads

Merge commit 'refs/top-bases/fix-stack-traverse_visitbp' into fix-stack-traverse_visitbp

Merge branch 'fix-stack-traverse_visitbp' into refs/top-bases/fix-branch

Merge branch 'fix-stack-traverse_impl' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-traverse_impl' into fix-stack-traverse_impl

Merge branch 'fix-stack-vn_open' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-vn_open' into fix-stack-vn_open

Merge branch 'fix-stack-dsl_dataset_destroy' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-dsl_dataset_destroy' into fix-stack-dsl_dataset_destroy

Merge branch 'fix-stack-dmu_objset_snapshot' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-dmu_objset_snapshot' into fix-stack-dmu_objset_snapshot

Merge branch 'fix-stack-noinline' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-noinline' into fix-stack-noinline

Merge branch 'fix-stack-dsl_deleg_get' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-dsl_deleg_get' into fix-stack-dsl_deleg_get

Merge branch 'fix-stack-dsl_dir_open_spa' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-dsl_dir_open_spa' into fix-stack-dsl_dir_open_spa

Merge branch 'fix-stack-lzjb' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-stack-lzjb' into fix-stack-lzjb

Merge branch 'fix-kstat-xuio' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-kstat-xuio' into fix-kstat-xuio

Merge branch 'fix-metaslab' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-metaslab' into fix-metaslab

Merge branch 'fix-current' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-current' into fix-current

Merge branch 'fix-error-handling' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-error-handling' into fix-error-handling

Merge branch 'fix-acl' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-acl' into fix-acl

Merge branch 'fix-deadcode' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-deadcode' into fix-deadcode

Merge branch 'fix-strncat' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-strncat' into fix-strncat

Merge branch 'fix-list' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-list' into fix-list

Merge branch 'fix-taskq' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-taskq' into fix-taskq

Merge branch 'fix-rwlocks' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-rwlocks' into fix-rwlocks

Merge branch 'fix-no-zmod' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-no-zmod' into fix-no-zmod

Merge branch 'fix-newlines' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-newlines' into fix-newlines

Merge branch 'fix-evict-dbufs' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-evict-dbufs' into fix-evict-dbufs

Merge branch 'fix-dnode-cons' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-dnode-cons' into fix-dnode-cons

Merge branch 'fix-dbuf_dirty_record_t' into refs/top-bases/fix-branch

Merge commit 'refs/top-bases/fix-dbuf_dirty_record_t' into fix-dbuf_dirty_record_t

Merge branch 'gcc-branch' into refs/top-bases/zfs-branch

Merge commit 'refs/top-bases/gcc-branch' into gcc-branch

Merge branch 'gcc-fortify-source' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-fortify-source' into gcc-fortify-source

Merge branch 'gcc-missing-braces' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-missing-braces' into gcc-missing-braces

Merge branch 'gcc-ident-pragmas' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-ident-pragmas' into gcc-ident-pragmas

Merge branch 'gcc-64bit-constants' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-64bit-constants' into gcc-64bit-constants

Merge branch 'gcc-unused' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-unused' into gcc-unused

Merge branch 'gcc-uninit' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-uninit' into gcc-uninit

Merge branch 'gcc-no-parenthesis' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-no-parenthesis' into gcc-no-parenthesis

Merge branch 'gcc-missing-case' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-missing-case' into gcc-missing-case

Merge branch 'gcc-invalid-prototype' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-invalid-prototype' into gcc-invalid-prototype

Merge branch 'gcc-init-pragmas' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-init-pragmas' into gcc-init-pragmas

Merge branch 'gcc-debug' into refs/top-bases/gcc-branch

Merge commit 'refs/top-bases/gcc-debug' into gcc-debug