Test windows builds on x86 & x64

.appveyor.yml

@@ -1,12 +1,18 @@
 build: off
-environment:
 
+platform:
+  - x86
+  - x64
+
+environment:
   matrix:
     - TOXENV: "py27"
 
 install:
   - cmd: git submodule update --init --recursive
-  - cmd: SET PATH=%PATH%;C:\Python27\Scripts;C:\MinGW\bin
+  - cmd: SET PATH=C:\MinGW\bin;%PATH%
+  - if %PLATFORM% == x64 SET PATH=C:\Python27-x64;C:\Python27-x64\Scripts;%PATH%
+  - if %PLATFORM% == x86 SET PATH=C:\Python27;C:\Python27\Scripts;%PATH%
   - cmd: pip install tox
 
 test_script:

scripts/install_devplatforms.py

@@ -15,6 +15,7 @@
 import json
 import subprocess
 import sys
+from platformio import util
 
 
 def main():
@@ -24,6 +25,10 @@ def main():
     for platform in platforms:
         if platform['forDesktop']:
             continue
+        # RISC-V GAP does not support Windows 86
+        if (util.get_systype() == "windows_x86"
+                and platform['name'] == "riscv_gap"):
+            continue
         subprocess.check_call(
             ["platformio", "platform", "install", platform['repository']])