diff --git a/appveyor.yml b/appveyor.yml
index 5f287b193d..26526fbee9 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -54,7 +54,7 @@ build_script:
     cp -r deps/minisat2-2.2.1 minisat-2.2.1
     patch -d minisat-2.2.1 -p1 < scripts/minisat-2.2.1-patch
     call "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" x64
-    sed -i "s/BUILD_ENV.*/BUILD_ENV = MSVC/" src/config.inc
+    sed -i "s/BUILD_ENV[ ]*=.*/BUILD_ENV = MSVC/" src/config.inc
     make -C src -j2
 
 test_script:
diff --git a/src/config.inc b/src/config.inc
index e1c1266f68..dc2c8f6a47 100644
--- a/src/config.inc
+++ b/src/config.inc
@@ -1,11 +1,12 @@
 # Build platform (use one of AUTO, Unix, OSX_Universal, MSVC, Cygwin, MinGW)
 BUILD_ENV = AUTO
 
-# Enable all warnings
-#CXXFLAGS += -Wall -Wno-long-long -Wno-sign-compare -Wno-parentheses -Wno-strict-aliasing -pedantic
-
-# Treat warnings as errors
-#CXXFLAGS += -Werror
+# Enable all warnings and treat them as errors
+ifeq ($(BUILD_ENV),MSVC)
+  #CXXFLAGS += /Wall /WX
+else
+  CXXFLAGS += -Wall -pedantic -Werror
+endif
 
 # Select optimisation or debug info
 #CXXFLAGS += -O2 -DNDEBUG