download and distribute compat db, cache db in case download fails

appveyor.yml

@@ -7,10 +7,12 @@ environment:
   QTDIR: C:\Qt\5.9\msvc2015_64
   LLVMLIBS: https://drive.google.com/uc?export=download&id=0B8A6NaxhQAGRY2k3Q2Yya05lcm8
   VULKAN: https://drive.google.com/uc?export=download&id=1A2eOMmCO714i0U7J0qI4aEMKnuWl8l_R
+  COMPATDB: https://rpcs3.net/compatibility?api=v1&export
 
 cache:
- - llvmlibs.7z -> appveyor.yml
- - vulkan.7z -> appveyor.yml
+- llvmlibs.7z -> appveyor.yml
+- vulkan.7z -> appveyor.yml
+- compat_database.dat
 
 install:
 - ps: | # set version env vars, update appveyor build version accordingly
@@ -65,6 +67,14 @@ after_build:
 - ps: | # remove unnecessary files
     rm .\bin\rpcs3.exp, .\bin\rpcs3.lib, .\bin\rpcs3.pdb
 
+- ps: | # prepare compatibility database for packaging
+    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+    $db = irm $env:COMPATDB -ea SilentlyContinue
+    if ($db -and $db.return_code -eq 0) {
+      $db | convertto-json -compress | out-file -encoding utf8 compat_database.dat
+    }
+    copy-item compat_database.dat .\bin\GuiConfigs\compat_database.dat
+
 - ps: | # package artifacts
     7z a $env:BUILD .\bin\*
     7z a openssl_win64.7z C:\OpenSSL-Win64\bin\libeay32.dll C:\OpenSSL-Win64\bin\ssleay32.dll