diff --git a/include/vkd3d_windows.h b/include/vkd3d_windows.h
index cf971f14..855b3240 100644
--- a/include/vkd3d_windows.h
+++ b/include/vkd3d_windows.h
@@ -139,7 +139,6 @@ typedef struct SECURITY_ATTRIBUTES SECURITY_ATTRIBUTES;
 
 # ifdef __GNUC__
 #  define DECLSPEC_SELECTANY __attribute__((weak))
-#  define DECLSPEC_HIDDEN __attribute__((visibility("hidden")))
 # endif
 
 /* Macros for COM interfaces */
@@ -190,6 +189,17 @@ typedef struct SECURITY_ATTRIBUTES SECURITY_ATTRIBUTES;
 # endif /* NONAMELESSUNION */
 #endif  /* __C89_NAMELESS */
 
+/* Define DECLSPEC_HIDDEN */
+#ifndef DECLSPEC_HIDDEN
+# if defined(__MINGW32__)
+#  define DECLSPEC_HIDDEN
+# elif defined(__GNUC__)
+#  define DECLSPEC_HIDDEN __attribute__((visibility("hidden")))
+# else
+#  define DECLSPEC_HIDDEN
+# endif
+#endif  /* DECLSPEC_HIDDEN */
+
 /* Define min() & max() macros */
 #ifndef min
 # define min(a, b) (((a) <= (b)) ? (a) : (b))
diff --git a/libs/vkd3d/debug.c b/libs/vkd3d/debug.c
index f67dad9f..6040fb94 100644
--- a/libs/vkd3d/debug.c
+++ b/libs/vkd3d/debug.c
@@ -84,8 +84,8 @@ void vkd3d_dbg_printf(enum vkd3d_dbg_level level, const char *function, const ch
 static char *get_buffer(void)
 {
     static char buffers[64][VKD3D_DEBUG_BUFFER_SIZE];
-    static unsigned int buffer_index;
-    unsigned int current_index;
+    static ULONG buffer_index;
+    ULONG current_index;
 
     current_index = InterlockedIncrement(&buffer_index) % ARRAY_SIZE(buffers);
     return buffers[current_index];
diff --git a/libs/vkd3d/vkd3d_common.h b/libs/vkd3d/vkd3d_common.h
index 54924177..472492a8 100644
--- a/libs/vkd3d/vkd3d_common.h
+++ b/libs/vkd3d/vkd3d_common.h
@@ -28,22 +28,24 @@
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
 
-#if HAVE_SYNC_ADD_AND_FETCH
+#ifndef _WIN32
+# if HAVE_SYNC_ADD_AND_FETCH
 static inline ULONG InterlockedIncrement(ULONG volatile *x)
 {
     return __sync_add_and_fetch(x, 1);
 }
-#else
-# error "InterlockedIncrement not implemented for this platform"
-#endif  /* HAVE_SYNC_ADD_AND_FETCH */
+# else
+#  error "InterlockedIncrement not implemented for this platform"
+# endif  /* HAVE_SYNC_ADD_AND_FETCH */
 
-#if HAVE_SYNC_SUB_AND_FETCH
+# if HAVE_SYNC_SUB_AND_FETCH
 static inline ULONG InterlockedDecrement(ULONG volatile *x)
 {
     return __sync_sub_and_fetch(x, 1);
 }
-#else
-# error "InterlockedDecrement not implemented for this platform"
-#endif
+# else
+#  error "InterlockedDecrement not implemented for this platform"
+# endif
+#endif  /* _WIN32 */
 
 #endif  /* __VKD3D_COMMON_H */
diff --git a/libs/vkd3d/vkd3d_debug.h b/libs/vkd3d/vkd3d_debug.h
index e5da92c7..8084890f 100644
--- a/libs/vkd3d/vkd3d_debug.h
+++ b/libs/vkd3d/vkd3d_debug.h
@@ -72,10 +72,10 @@ static inline const char *debugstr_guid(const GUID *guid)
     if (!guid)
         return "(null)";
 
-    return vkd3d_dbg_sprintf("{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",
-            guid->Data1, guid->Data2, guid->Data3, guid->Data4[0], guid->Data4[1],
-            guid->Data4[2], guid->Data4[3], guid->Data4[4], guid->Data4[5],
-            guid->Data4[6], guid->Data4[7]);
+    return vkd3d_dbg_sprintf("{%08lx-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",
+            (unsigned long)guid->Data1, guid->Data2, guid->Data3, guid->Data4[0],
+            guid->Data4[1], guid->Data4[2], guid->Data4[3], guid->Data4[4],
+            guid->Data4[5], guid->Data4[6], guid->Data4[7]);
 }
 
 #endif  /* __VKD3D_DEBUG_H */