diff --git a/.appveyor.yml b/.appveyor.yml
index 48b51af0b..457f0883c 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -6,29 +6,34 @@ branches:
 
 clone_depth: 10
 
-os: Visual Studio 2015
+environment:
+  matrix:
+    - GENERATOR: "Visual Studio 14 2015"
+      CONFIGURATION: Release
+      TOOLSET: v140_xp
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2015"
+    - GENERATOR: "Visual Studio 14 2015 Win64"
+      CONFIGURATION: Release
+      TOOLSET: v140_xp
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2015"
+    - GENERATOR: "Visual Studio 15 2017"
+      CONFIGURATION: Release
+      TOOLSET: v141_xp
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2017"
+    - GENERATOR: "Visual Studio 15 2017 Win64"
+      CONFIGURATION: Release
+      TOOLSET: v141_xp
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2017"
+    - GENERATOR: "Visual Studio 14 2015 Win64"
+      CONFIGURATION: Debug
+      TOOLSET: v140
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2015"
 
-platform: 
-  - Win32
-  - x64
-
-configuration:
-  - Debug
-  - Release
-
-before_build:
+build_script:
   - md build
   - cd build
-  - if "%PLATFORM%"=="Win32" set CMAKE_GENERATOR_NAME=Visual Studio 14 2015
-  - if "%PLATFORM%"=="x64"   set CMAKE_GENERATOR_NAME=Visual Studio 14 2015 Win64
-  - cmake -G "%CMAKE_GENERATOR_NAME%" -T "v140_xp"
-    -DCMAKE_BUILD_TYPE="%CONFIGURATION%"
-    ..
-
-build:
-  project: build\GZDoom.sln
-  parallel: true
-  verbosity: minimal
+  - cmake -G "%GENERATOR%" -T "%TOOLSET%" ..
+  - cmake --build . --config "%CONFIGURATION%"
 
 after_build:
   - set OUTPUT_DIR=%APPVEYOR_BUILD_FOLDER%\build\%CONFIGURATION%\
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c6bf7f74e..885cf60b6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -60,7 +60,6 @@ if( WIN32 )
 		( MSVC15 AND NOT CMAKE_GENERATOR_TOOLSET STREQUAL "v141_xp" ) )		# For VS 2017.
 		# for modern Windows SDKs the DirectX headers should be available by default.
 		set( DX_dinput8_LIBRARY dinput8 )
-		set( DX_dxguid_LIBRARY dxguid )
 	else()
 		
 		find_path( D3D_INCLUDE_DIR d3d9.h
@@ -97,9 +96,6 @@ if( WIN32 )
 		find_library( DX_dinput8_LIBRARY dinput8
 			PATHS ENV DXSDK_DIR
 			PATH_SUFFIXES Lib Lib/${XBITS} )
-		find_library( DX_dxguid_LIBRARY dxguid
-			PATHS ENV DXSDK_DIR
-			PATH_SUFFIXES Lib Lib/${XBITS} )
 
 		# Modern versions of the Windows SDK include dinput8.lib. Unfortunately,
 		# CMake cannot find these libraries via find_library.
@@ -108,11 +104,6 @@ if( WIN32 )
 			set( DX_dinput8_LIBRARY dinput8 )
 		endif()
 
-		# Modern versions of the Windows SDK do NOT include dxguid.lib. Its contents
-		# were moved to dinput8.lib.
-		if( NOT DX_dxguid_LIBRARY )
-			message( STATUS "Could not find dxguid.lib. Build may fail on old Windows SDKs.")
-		endif()
 	endif()
 
 	set( ZDOOM_LIBS
@@ -133,9 +124,6 @@ if( WIN32 )
 		set( ZDOOM_LIBS ${ZDOOM_LIBS} DelayImp )
 	endif()
 
-	if( DX_dxguid_LIBRARY )
-		list( APPEND ZDOOM_LIBS "${DX_dxguid_LIBRARY}" )
-	endif()
 else()
 	if( APPLE )
 		set( NO_GTK ON )
diff --git a/src/cmdlib.cpp b/src/cmdlib.cpp
index 7013c6a60..f667610c0 100644
--- a/src/cmdlib.cpp
+++ b/src/cmdlib.cpp
@@ -477,16 +477,45 @@ const char *myasctime ()
 void DoCreatePath(const char *fn)
 {
 	char drive[_MAX_DRIVE];
-	char path[PATH_MAX];
-	char p[PATH_MAX];
-	int i;
+	char dir[_MAX_DIR];
+	_splitpath_s(fn, drive, sizeof drive, dir, sizeof dir, nullptr, 0, nullptr, 0);
 
-	_splitpath(fn,drive,path,NULL,NULL);
-	_makepath(p,drive,path,NULL,NULL);
-	i=(int)strlen(p);
-	if (p[i-1]=='/' || p[i-1]=='\\') p[i-1]=0;
-	if (*path) DoCreatePath(p);
-	_mkdir(p);
+	if ('\0' == *dir)
+	{
+		// Root/current/parent directory always exists
+		return;
+	}
+
+	char path[PATH_MAX];
+	_makepath_s(path, sizeof path, drive, dir, nullptr, nullptr);
+
+	if ('\0' == *path)
+	{
+		// No need to process empty relative path
+		return;
+	}
+
+	// Remove trailing path separator(s)
+	for (size_t i = strlen(path); 0 != i; --i)
+	{
+		char& lastchar = path[i - 1];
+
+		if ('/' == lastchar || '\\' == lastchar)
+		{
+			lastchar = '\0';
+		}
+		else
+		{
+			break;
+		}
+	}
+
+	// Create all directories for given path
+	if ('\0' != *path)
+	{
+		DoCreatePath(path);
+		_mkdir(path);
+	}
 }
 
 void CreatePath(const char *fn)
diff --git a/src/win32/win32video.cpp b/src/win32/win32video.cpp
index 93da57c69..0546863cb 100644
--- a/src/win32/win32video.cpp
+++ b/src/win32/win32video.cpp
@@ -284,7 +284,9 @@ void Win32Video::InitDDraw ()
 	if (FAILED(dderr))
 		I_FatalError ("Could not create DirectDraw object: %08lx", dderr);
 
-	dderr = ddraw1->QueryInterface (IID_IDirectDraw2, (LPVOID*)&DDraw);
+	static const GUID IDIRECTDRAW2_GUID = { 0xB3A6F3E0, 0x2B43, 0x11CF, 0xA2, 0xDE, 0x00, 0xAA, 0x00, 0xB9, 0x33, 0x56 };
+
+	dderr = ddraw1->QueryInterface (IDIRECTDRAW2_GUID, (LPVOID*)&DDraw);
 	if (FAILED(dderr))
 	{
 		ddraw1->Release ();