Enable mingw64 builds (7)

.appveyor.yml

@@ -52,15 +52,17 @@ build_script:
     - b2.exe -j4 toolset=msvc address-model=64 architecture=x86 link=static --with-program_options --with-filesystem --with-system --with-test --with-atomic --with-thread --with-date_time --with-chrono --with-regex --with-random --with-context --with-coroutine stage
     - b2.exe -j4 toolset=gcc architecture=x86 link=static --with-program_options --with-filesystem --with-system --with-test --with-atomic --with-thread --with-date_time --with-chrono --with-regex --with-random --with-context --with-coroutine stage
     - cd %APPVEYOR_BUILD_FOLDER%
-    # Building examples.
-    - qmake "BOOST_PATH=%BOOST%" BoostBook.pro
 
 after_build:
 before_test:
 test_script:
-    - nmake
+    # Building examples.
+    - qmake "BOOST_PATH=%BOOST%" BoostBook.pro
+    - nmake /NOLOGO
     - python ./test.py
-    - nmake clean
+    - nmake distclean
+
+    - qmake -unix "BOOST_PATH=%BOOST%" BoostBook.pro
     - mingw32-make
     - python ./test.py