diff --git a/CMakeLists.txt b/CMakeLists.txt
index f0c50bf2..670ed435 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,8 +31,8 @@ if (HAVE_STD_CPP11_FLAG)
   # It may not in MinGW due to bug http://sourceforge.net/p/mingw/bugs/2024/.
   check_cxx_source_compiles("
     #include <unistd.h>
-    int main() {}" FMT_CPP11_IO_H)
-  if (FMT_CPP11_CMATH AND FMT_CPP11_IO_H)
+    int main() {}" FMT_CPP11_UNISTD_H)
+  if (FMT_CPP11_CMATH AND FMT_CPP11_UNISTD_H)
     set(CPP11_FLAG -std=c++11)
   endif ()
   set(CMAKE_REQUIRED_FLAGS )
diff --git a/appveyor.yml b/appveyor.yml
index 23d1afa0..dfebef22 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,14 +1,14 @@
 environment:
   CTEST_OUTPUT_ON_FAILURE: 1
   matrix:
-#  - BUILD: msvc
-#    CONFIG: Debug
-#  - BUILD: msvc
-#    CONFIG: Release
+  - BUILD: msvc
+    CONFIG: Debug
+  - BUILD: msvc
+    CONFIG: Release
   - BUILD: mingw
     CONFIG: Debug
-#  - BUILD: mingw
-#    CONFIG: Release
+  - BUILD: mingw
+    CONFIG: Release
 
 build_script:
   - python support/appveyor-build.py