diff --git a/src/autosegs.h b/src/autosegs.h
index b873602ed..a58b6d14d 100644
--- a/src/autosegs.h
+++ b/src/autosegs.h
@@ -41,13 +41,13 @@
 #define CREG_SECTION "__DATA,creg"
 #define GREG_SECTION "__DATA,greg"
 #define MREG_SECTION "__DATA,mreg"
-#define MREG_SECTION "__DATA,yreg"
+#define YREG_SECTION "__DATA,yreg"
 #else
 #define AREG_SECTION "areg"
 #define CREG_SECTION "creg"
 #define GREG_SECTION "greg"
 #define MREG_SECTION "mreg"
-#define GREG_SECTION "yreg"
+#define YREG_SECTION "yreg"
 #endif
 #endif
 
diff --git a/src/compatibility.cpp b/src/compatibility.cpp
index 9192bfe5e..a2cf321f8 100644
--- a/src/compatibility.cpp
+++ b/src/compatibility.cpp
@@ -214,7 +214,7 @@ CCMD (mapchecksum)
 	{
 		Printf("Usage: mapchecksum <map> ...\n");
 	}
-	for (unsigned int i = 1; i < argv.argc(); ++i)
+	for (int i = 1; i < argv.argc(); ++i)
 	{
 		map = P_OpenMapData(argv[i]);
 		if (map == NULL)
@@ -225,7 +225,7 @@ CCMD (mapchecksum)
 		{
 			map->GetChecksum(cksum);
 			delete map;
-			for (int j = 0; j < sizeof(cksum); ++j)
+			for (size_t j = 0; j < sizeof(cksum); ++j)
 			{
 				Printf("%02X", cksum[j]);
 			}
diff --git a/src/md5.cpp b/src/md5.cpp
index 1906f77d1..11d41d577 100644
--- a/src/md5.cpp
+++ b/src/md5.cpp
@@ -101,7 +101,7 @@ void MD5Context::Update(FileReader *file, unsigned len)
 
 	while (len != 0)
 	{
-		t = MIN(len, sizeof(readbuf));
+		t = MIN<long>(len, sizeof(readbuf));
 		len -= t;
 		t = file->Read(readbuf, t);
 		Update(readbuf, t);
@@ -249,8 +249,6 @@ MD5Transform(DWORD buf[4], const DWORD in[16])
 
 #endif
 
-#include "c_dispatch.h"
-
 //==========================================================================
 //
 // CCMD md5sum
@@ -259,6 +257,9 @@ MD5Transform(DWORD buf[4], const DWORD in[16])
 //
 //==========================================================================
 
+#include "c_dispatch.h"
+#include <errno.h>
+
 CCMD (md5sum)
 {
 	if (argv.argc() < 2)
diff --git a/src/teaminfo.cpp b/src/teaminfo.cpp
index 39fe58ee3..90dfb2c93 100644
--- a/src/teaminfo.cpp
+++ b/src/teaminfo.cpp
@@ -149,7 +149,7 @@ void FTeam::ParseTeamInfo ()
 
 	if (Teams.Size () < 2)
 		I_FatalError ("ParseTeamInfo: At least two teams must be defined in TEAMINFO.");
-	else if (Teams.Size () > TEAM_MAXIMUM)
+	else if (Teams.Size () > (unsigned)TEAM_MAXIMUM)
 		I_FatalError ("ParseTeamInfo: Too many teams defined. (Maximum: %d)", TEAM_MAXIMUM);
 }