contrib/packaging/wix/doc.wxs

tests: look for ensurepip before using venv

Debian appears to cripple the venv module by default by
removing the associated ensurepip functionality. (The module
isn't present at all.) This caused test-install.t to fail when
using the Debian python3 unless the python3-venv package was
installed.

This commit introduces a new hghave requirement for detecting
ensurepip and makes the Python 3 install variant conditional on
its presence. This should make test-install.t pass when
using an incomplete Debian Python.

Differential Revision: https://phab.mercurial-scm.org/D7228

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">

  <?include guids.wxi ?>
  <?include defines.wxi ?>

  <Fragment>
    <ComponentGroup Id="docFolder">
      <ComponentRef Id="doc.hg.1.html" />
      <ComponentRef Id="doc.hgignore.5.html" />
      <ComponentRef Id="doc.hgrc.5.html" />
      <ComponentRef Id="doc.style.css" />
    </ComponentGroup>
  </Fragment>

  <Fragment>
    <DirectoryRef Id="INSTALLDIR">
      <Directory Id="docdir" Name="doc" FileSource="$(var.SourceDir)">
        <Component Id="doc.hg.1.html" Guid="$(var.doc.hg.1.html.guid)" Win64='$(var.IsX64)'>
          <File Name="hg.1.html" KeyPath="yes">
            <Shortcut Id="hg1StartMenu" Directory="ProgramMenuDir"
                      Name="Mercurial Command Reference"
                      Icon="hgIcon.ico" IconIndex="0" Advertise="yes"
            />
          </File>
        </Component>
        <Component Id="doc.hgignore.5.html" Guid="$(var.doc.hgignore.5.html.guid)" Win64='$(var.IsX64)'>
          <File Name="hgignore.5.html" KeyPath="yes">
            <Shortcut Id="hgignore5StartMenu" Directory="ProgramMenuDir"
                      Name="Mercurial Ignore Files"
                      Icon="hgIcon.ico" IconIndex="0" Advertise="yes"
            />
          </File>
        </Component>
        <Component Id="doc.hgrc.5.html" Guid="$(var.doc.hgrc.5.html)" Win64='$(var.IsX64)'>
          <File Name="hgrc.5.html" KeyPath="yes">
            <Shortcut Id="hgrc5StartMenu" Directory="ProgramMenuDir"
                      Name="Mercurial Configuration Files"
                      Icon="hgIcon.ico" IconIndex="0" Advertise="yes"
            />
          </File>
        </Component>
        <Component Id="doc.style.css" Guid="$(var.doc.style.css)" Win64='$(var.IsX64)'>
          <File Name="style.css" KeyPath="yes" />
        </Component>
      </Directory>
    </DirectoryRef>
  </Fragment>

</Wix>