diff --git a/appveyor.yml b/appveyor.yml
index 6d03dde..76e605f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -52,6 +52,7 @@ platform:
 configuration: Release
 
 install:
+  - 'set GCOV_PREFIX=%APPVEYOR_BUILD_FOLDER%'
   - "%CYG_BASH% -lc 'cd $APPVEYOR_BUILD_FOLDER; ./autogen.sh'"
   - '%CYG_BASH% -lc "cd $APPVEYOR_BUILD_FOLDER; exec 0</dev/null; ./configure CC=i686-w64-mingw32-gcc CFLAGS=\"-g -O0\" --enable-gcov"'