fix appveyor test

was mixing `*.o` object files from different compilation settings

diff --git a/appveyor.yml b/appveyor.yml
index 5d77b31034816866d59f7a47951efc001d17e9c4..91568e4840a7da18650b1e6cda34fd1860b26268 100644 (file)
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -285,5 +285,6 @@
   - ECHO Testing %COMPILER% %PLATFORM% %CONFIGURATION%
   - if [%HOST%]==[mingw] (
       set "CC=%COMPILER%" &&
+      make clean &&
       make check
     )