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    <p>Hi Nikolaus,</p>
    <p>I came across a similar question a year ago, but I had to find
      some time for digging it out.<br>
      So back then I wanted to use <span class="blob-code-inner"><span
          class="pl-s"><span class="pl-smi">DEB_TARGET_GNU_TYPE to
            identify the long compiler name, arm-linux-gnueabihf.<br>
          </span></span></span></p>
    <p><span class="blob-code-inner"><span class="pl-s"><span
            class="pl-smi">Now back in Wheezy, we only had BUILD_* and
            HOST_*. Quoting the Debian Wiki Page on cross-build
            packaging [1]:<br>
            "</span></span></span><span class="blob-code-inner"><span
          class="pl-s"><span class="pl-smi">HOST is the machine we are
            building for"<br>
            "</span></span></span>BUILD is the machine we are building
      on"</p>
    <p>So HOST_* is what we want to use here!</p>
    <p>I don't fully understand what TARGET means. Reading in the gcc
      manual [2] about build, host and target I understand this:<br>
      We are building software on a machine (BUILD), to execute on
      another machine (HOST). And then we can have a TARGET machine that
      our newly built software may produce code for, if it is a
      compiler, assembler or otherwise generating tool.</p>
    <p>So I conclude that we should be using HOST, not only on Wheezy,
      but also on later releases as this is most accurate to our
      use-case.<br>
    </p>
    <p>br<br>
      Josua<br>
    </p>
    <p>[1] <a class="moz-txt-link-freetext" href="https://wiki.debian.org/CrossBuildPackagingGuidelines">https://wiki.debian.org/CrossBuildPackagingGuidelines</a><br>
      [2]
      <a class="moz-txt-link-freetext" href="https://gcc.gnu.org/onlinedocs/gcc-4.0.2/gccint/Configure-Terms.html">https://gcc.gnu.org/onlinedocs/gcc-4.0.2/gccint/Configure-Terms.html</a><br>
    </p>
    <br>
    <div class="moz-cite-prefix">Am 26.03.2018 um 14:07 schrieb H.
      Nikolaus Schaller:<br>
    </div>
    <blockquote type="cite"
      cite="mid:563EB93C-C8F8-4C6A-802E-2BEA4C9E6FB2@goldelico.com">
      <pre wrap="">Hi Jonas,

</pre>
      <blockquote type="cite">
        <pre wrap="">Am 26.03.2018 um 13:17 schrieb Jonas Smedegaard <a class="moz-txt-link-rfc2396E" href="mailto:jonas@jones.dk"><jonas@jones.dk></a>:

Quoting H. Nikolaus Schaller (2018-03-26 12:43:56)
</pre>
        <blockquote type="cite">
          <pre wrap="">Hi,
nobody with an idea or knowledge?

BR,
Nikolaus

</pre>
          <blockquote type="cite">
            <pre wrap="">Am 18.03.2018 um 15:37 schrieb H. Nikolaus Schaller <a class="moz-txt-link-rfc2396E" href="mailto:hns@goldelico.com"><hns@goldelico.com></a>:

Another topic:

I am trying to build it on/for wheezy, but ./mkqtspec.sh fails with:

     dpkg-architecture: error: DEB_TARGET_ARCH is not a supported variable name

Jessie reports:

root@letux:# dpkg-architecture
DEB_BUILD_ARCH=armhf
DEB_BUILD_ARCH_BITS=32
DEB_BUILD_ARCH_CPU=arm
DEB_BUILD_ARCH_ENDIAN=little
DEB_BUILD_ARCH_OS=linux
DEB_BUILD_GNU_CPU=arm
DEB_BUILD_GNU_SYSTEM=linux-gnueabihf
DEB_BUILD_GNU_TYPE=arm-linux-gnueabihf
DEB_BUILD_MULTIARCH=arm-linux-gnueabihf
DEB_HOST_ARCH=armhf
DEB_HOST_ARCH_BITS=32
DEB_HOST_ARCH_CPU=arm
DEB_HOST_ARCH_ENDIAN=little
DEB_HOST_ARCH_OS=linux
DEB_HOST_GNU_CPU=arm
DEB_HOST_GNU_SYSTEM=linux-gnueabihf
DEB_HOST_GNU_TYPE=arm-linux-gnueabihf
DEB_HOST_MULTIARCH=arm-linux-gnueabihf
DEB_TARGET_ARCH=armhf
DEB_TARGET_ARCH_BITS=32
DEB_TARGET_ARCH_CPU=arm
DEB_TARGET_ARCH_ENDIAN=little
DEB_TARGET_ARCH_OS=linux
DEB_TARGET_GNU_CPU=arm
DEB_TARGET_GNU_SYSTEM=linux-gnueabihf
DEB_TARGET_GNU_TYPE=arm-linux-gnueabihf
DEB_TARGET_MULTIARCH=arm-linux-gnueabihf
root@letux:#

Wheezy reports:

root@letux:/# dpkg-architecture
DEB_BUILD_ARCH=armhf
DEB_BUILD_ARCH_BITS=32
DEB_BUILD_ARCH_CPU=arm
DEB_BUILD_ARCH_ENDIAN=little
DEB_BUILD_ARCH_OS=linux
DEB_BUILD_GNU_CPU=arm
DEB_BUILD_GNU_SYSTEM=linux-gnueabihf
DEB_BUILD_GNU_TYPE=arm-linux-gnueabihf
DEB_BUILD_MULTIARCH=arm-linux-gnueabihf
DEB_HOST_ARCH=armhf
DEB_HOST_ARCH_BITS=32
DEB_HOST_ARCH_CPU=arm
DEB_HOST_ARCH_ENDIAN=little
DEB_HOST_ARCH_OS=linux
DEB_HOST_GNU_CPU=arm
DEB_HOST_GNU_SYSTEM=linux-gnueabihf
DEB_HOST_GNU_TYPE=arm-linux-gnueabihf
DEB_HOST_MULTIARCH=arm-linux-gnueabihf
root@letux:/#

So can we safely replace DEB_TARGET_ARCH by DEB_BUILD_ARCH
in DEB_TARGET_ARCH=$(dpkg-architecture -qDEB_TARGET_ARCH) ?
</pre>
          </blockquote>
        </blockquote>
        <pre wrap="">
"man dpkg-architecture" says:

</pre>
        <blockquote type="cite">
          <pre wrap="">DEB_BUILD_ARCH
 The Debian architecture of the build machine.
</pre>
        </blockquote>
      </blockquote>
      <pre wrap="">
ok.

</pre>
      <blockquote type="cite">
        <pre wrap="">
and

</pre>
        <blockquote type="cite">
          <pre wrap="">DEB_TARGET_ARCH
 The Debian architecture of the target machine (since dpkg 1.17.14).
</pre>
        </blockquote>
      </blockquote>
      <pre wrap="">
ok. So we can use the same since the build is not a cross-build or anything.

</pre>
      <blockquote type="cite">
        <pre wrap="">
dpkg version in wheezy is too old:
<a class="moz-txt-link-freetext" href="https://packages.debian.org/source/oldoldstable/dpkg">https://packages.debian.org/source/oldoldstable/dpkg</a>
</pre>
      </blockquote>
      <pre wrap="">
Well, for building a package for wheezy it should never be too old...
Only some source code could be too new :)

</pre>
      <blockquote type="cite">
        <pre wrap="">
If build machine is same architecture as target machine, then you can
reuse, else not.
</pre>
      </blockquote>
      <pre wrap="">
So does this mean the following?

* use DEB_TARGET_ARCH if defined
* fall back to DEB_BUILD_ARCH otherwise

I.e. replace it by:

DEB_TARGET_ARCH=$(dpkg-architecture -qDEB_TARGET_ARCH 2>/dev/null)
[ "$DEB_TARGET_ARCH" ] || DEB_TARGET_ARCH=$(dpkg-architecture -qDEB_BUILD_ARCH

BR and thanks,
Nikolaus

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