Okay, fine, we'll install php Cees-Jan Kiewiet's way.

appveyor.yml

@@ -20,8 +20,8 @@ install:
   - git clone -q https://github.com/acquia/DevDesktopCommon.git #For tar, cksum, ...
   - SET PATH=%APPVEYOR_BUILD_FOLDER%/DevDesktopCommon/bintools-win/msys/bin;%PATH%
   - SET PATH=C:\Program Files\MySql\MySQL Server 5.7\bin\;%PATH%
-  #Install PHP
-  - cinst -y --ignore-checksums php --version 7.0.12
+  #Install PHP per https://blog.wyrihaximus.net/2016/11/running-php-unit-tests-on-windows-using-appveyor-and-chocolatey/
+  - cinst --ignore-checksums -y php --version ((choco search php --exact --all-versions -r | select-string -pattern $Env:php_ver_target | Select-Object -first 1) -replace '[php|]','')
   - cd c:\tools\php
   - copy php.ini-production php.ini