[appveyor] restrict MinGW to Win32 as win_ucontext does not work on 64bits

diff --git a/appveyor.yml b/appveyor.yml
index ff931d6..67d9772 100644 (file)
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -23,6 +23,7 @@ environment:
     - COMPILER: MSVC15
       PLATFORM: Win32
     - COMPILER: MinGW-w64
+      PLATFORM: Win32
 
 #    - COMPILER: MSVC15
 #      PLATFORM: x64