diff --git a/src/d_stats.cpp b/src/d_stats.cpp
index d2005d4cd..ebec250bb 100644
--- a/src/d_stats.cpp
+++ b/src/d_stats.cpp
@@ -139,7 +139,7 @@ static int GetOSVersion()
 	if (sizeof(void*) == 4)	// 32 bit
 	{
 		BOOL res;
-		if (IsWow64Process(GetCurrentProcess(), &res))
+		if (IsWow64Process(GetCurrentProcess(), &res) && res)
 		{
 			return 6;
 		}
diff --git a/src/p_glnodes.cpp b/src/p_glnodes.cpp
index 540812a0a..7d0e37339 100644
--- a/src/p_glnodes.cpp
+++ b/src/p_glnodes.cpp
@@ -45,6 +45,7 @@
 
 #endif
 
+#include <zlib.h>
 #include "templates.h"
 #include "m_alloc.h"
 #include "m_argv.h"
diff --git a/src/resourcefiles/resourcefile.cpp b/src/resourcefiles/resourcefile.cpp
index 17c7e8739..adb484d32 100644
--- a/src/resourcefiles/resourcefile.cpp
+++ b/src/resourcefiles/resourcefile.cpp
@@ -34,6 +34,7 @@
 **
 */
 
+#include <zlib.h>
 #include "resourcefile.h"
 #include "cmdlib.h"
 #include "w_wad.h"
diff --git a/src/serializer.cpp b/src/serializer.cpp
index c41fec1f3..75f96d581 100644
--- a/src/serializer.cpp
+++ b/src/serializer.cpp
@@ -37,6 +37,7 @@
 #define RAPIDJSON_HAS_CXX11_RANGE_FOR 1
 #define RAPIDJSON_PARSE_DEFAULT_FLAGS kParseFullPrecisionFlag
 
+#include <zlib.h>
 #include "rapidjson/rapidjson.h"
 #include "rapidjson/writer.h"
 #include "rapidjson/prettywriter.h"
diff --git a/src/sound/i_music.cpp b/src/sound/i_music.cpp
index e93ba1b09..273ddb115 100644
--- a/src/sound/i_music.cpp
+++ b/src/sound/i_music.cpp
@@ -45,6 +45,7 @@
 #include <ctype.h>
 #include <assert.h>
 #include <stdio.h>
+#include <zlib.h>
 
 #include "i_musicinterns.h"
 #include "doomtype.h"
diff --git a/src/sound/timiditypp/configfile.cpp b/src/sound/timiditypp/configfile.cpp
index 4d728f5ed..1344a9cd6 100644
--- a/src/sound/timiditypp/configfile.cpp
+++ b/src/sound/timiditypp/configfile.cpp
@@ -20,6 +20,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 
 #include <stdio.h>
 #include <string.h>
+#include <stdint.h>
 
 #include <time.h>
 
diff --git a/src/sound/timiditypp/sfitem.cpp b/src/sound/timiditypp/sfitem.cpp
index 1e2173c1d..fc7d55e69 100644
--- a/src/sound/timiditypp/sfitem.cpp
+++ b/src/sound/timiditypp/sfitem.cpp
@@ -24,6 +24,7 @@
  *================================================================*/
 
 #include <stdio.h>
+#include <stdint.h>
 #include "timidity.h"
 #include "common.h"
 #include "sflayer.h"
@@ -95,4 +96,4 @@ const LayerItem static_layer_items[SF_EOF] = {
 	{L_OVWRT, T_NOCONV, 0, 127, -1}, /* rootKey */
 };
 
-}
\ No newline at end of file
+}
diff --git a/src/sound/timiditypp/timidity.h b/src/sound/timiditypp/timidity.h
index 0c7850568..5fe3667f6 100644
--- a/src/sound/timiditypp/timidity.h
+++ b/src/sound/timiditypp/timidity.h
@@ -30,6 +30,7 @@
 
 #include "controls.h"
 #include "mblock.h"
+#include <stdint.h>
 
 #ifdef _MSC_VER
 #pragma warning(disable:4244)	// double->float truncation occurs so often in here that it's pointless to fix it all.