diff --git a/neo/framework/Common.cpp b/neo/framework/Common.cpp
index e54b35c0..8744adf5 100644
--- a/neo/framework/Common.cpp
+++ b/neo/framework/Common.cpp
@@ -48,6 +48,8 @@ If you have questions concerning this license or the applicable additional terms
 
 #include "../sys/sys_savegame.h"
 
+#include "idlib/sys/sys_defines.h"
+
 #if defined( _DEBUG )
 #define BUILD_DEBUG "-debug"
 #else
@@ -2020,12 +2022,7 @@ CONSOLE_COMMAND( testSIMD, "test SIMD code", NULL )
 // RB begin
 CONSOLE_COMMAND( testFormattingSizes, "test printf format security", 0 )
 {
-#ifdef _MSC_VER
-	common->Printf( " sizeof( int32 ): %Iu bytes\n", sizeof( int32 ) );
-	common->Printf( " sizeof( int64 ): %Iu bytes\n", sizeof( int64 ) );
-#else
-	common->Printf( " sizeof( int32 ): %zu bytes\n", sizeof( int32 ) );
-	common->Printf( " sizeof( int64 ): %zu bytes\n", sizeof( int64 ) );
-#endif
+	common->Printf( " sizeof( int32 ): %" PRIuSIZE " bytes\n", sizeof( int32 ) );
+	common->Printf( " sizeof( int64 ): %" PRIuSIZE " bytes\n", sizeof( int64 ) );
 }
 // RB end
diff --git a/neo/framework/File.cpp b/neo/framework/File.cpp
index 7bb61ce8..0684de3e 100644
--- a/neo/framework/File.cpp
+++ b/neo/framework/File.cpp
@@ -31,6 +31,7 @@ If you have questions concerning this license or the applicable additional terms
 #pragma hdrstop
 
 #include "Unzip.h"
+#include "idlib/sys/sys_defines.h"
 
 /*
 =================
@@ -844,11 +845,7 @@ int idFile_Memory::Write( const void* buffer, int len )
 	{
 		if( maxSize != 0 )
 		{
-#ifdef _MSC_VER
-			common->Error( "idFile_Memory::Write: exceeded maximum size %Iu", maxSize );
-#else
-			common->Error( "idFile_Memory::Write: exceeded maximum size %zu", maxSize );
-#endif
+			common->Error( "idFile_Memory::Write: exceeded maximum size %" PRIuSIZE "", maxSize );
 			return 0;
 		}
 		int extra = granularity * ( 1 + alloc / granularity );
@@ -934,13 +931,7 @@ void idFile_Memory::PreAllocate( size_t len )
 	{
 		if( maxSize != 0 )
 		{
-// RB begin
-#ifdef _MSC_VER
-			idLib::Error( "idFile_Memory::SetLength: exceeded maximum size %Iu", maxSize );
-#else
-			idLib::Error( "idFile_Memory::SetLength: exceeded maximum size %zu", maxSize );
-#endif
-// RB end
+			idLib::Error( "idFile_Memory::SetLength: exceeded maximum size %" PRIuSIZE "", maxSize );
 		}
 		char* newPtr = ( char* )Mem_Alloc( len, TAG_IDFILE );
 		if( allocated > 0 )
@@ -1126,13 +1117,7 @@ void idFile_Memory::TruncateData( size_t len )
 {
 	if( len > allocated )
 	{
-// RB begin
-#ifdef _MSV_VER
-		idLib::Error( "idFile_Memory::TruncateData: len (%Iu) exceeded allocated size (%Iu)", len, allocated );
-#else
-		idLib::Error( "idFile_Memory::TruncateData: len (%zu) exceeded allocated size (%zu)", len, allocated );
-#endif
-// RB end
+		idLib::Error( "idFile_Memory::TruncateData: len (%" PRIuSIZE ") exceeded allocated size (%" PRIuSIZE ")", len, allocated );
 	}
 	else
 	{
@@ -2126,5 +2111,3 @@ CONSOLE_COMMAND( testEndianNessReset, "Tests the read/write compatibility betwee
 {
 	fileSystem->RemoveFile( testEndianNessFilename );
 }
-
-
diff --git a/neo/framework/Zip.cpp b/neo/framework/Zip.cpp
index 4246d520..fb1eca30 100644
--- a/neo/framework/Zip.cpp
+++ b/neo/framework/Zip.cpp
@@ -36,6 +36,7 @@ Contains external code for building ZipFiles.
 */
 
 #include "Zip.h"
+#include "idlib/sys/sys_defines.h"
 
 // #undef STDC
 
@@ -504,13 +505,7 @@ bool idZipBuilder::CreateZipFileFromFiles( const idList< idFile_Memory* >& srcFi
 					errcode = zipWriteInFileInZip( zf, buffer.Ptr(), ( unsigned int )bytesRead );
 					if( errcode != ZIP_OK )
 					{
-// RB begin
-#ifdef _MSC_VER
-						idLib::Warning( "Error writing to zipfile (%Iu bytes)!", bytesRead );
-#else
-						idLib::Warning( "Error writing to zipfile (%zu bytes)!", bytesRead );
-#endif
-// RB end
+						idLib::Warning( "Error writing to zipfile (%" PRIuSIZE " bytes)!", bytesRead );
 						continue;
 					}
 				}
@@ -618,13 +613,7 @@ bool idZipBuilder::AddFile( zipFile zf, idFile_Memory* src, bool deleteFile )
 				errcode = zipWriteInFileInZip( zf, buffer.Ptr(), ( unsigned int )bytesRead );
 				if( errcode != ZIP_OK )
 				{
-// RB begin
-#ifdef _MSC_VER
-					idLib::Warning( "Error writing to zipfile (%Iu bytes)!", bytesRead );
-#else
-					idLib::Warning( "Error writing to zipfile (%zu bytes)!", bytesRead );
-#endif
-// RB end
+					idLib::Warning( "Error writing to zipfile (%" PRIuSIZE " bytes)!", bytesRead );
 					continue;
 				}
 			}
diff --git a/neo/idlib/sys/sys_defines.h b/neo/idlib/sys/sys_defines.h
index 11d3fee8..82940727 100644
--- a/neo/idlib/sys/sys_defines.h
+++ b/neo/idlib/sys/sys_defines.h
@@ -257,3 +257,22 @@ extern volatile int ignoredReturnValue;
 #define MIN_UNSIGNED_TYPE( x )	0
 
 #endif
+
+
+/*
+ * Macros for format conversion specifications for integer arguments of type
+ * size_t or ssize_t.
+ */
+#ifdef _MSV_VER
+
+#define PRIiSIZE "Ii"
+#define PRIuSIZE "Iu"
+#define PRIxSIZE "Ix"
+
+#else // ifdef _MSV_VER
+
+#define PRIiSIZE "zi"
+#define PRIuSIZE "zu"
+#define PRIxSIZE "zx"
+
+#endif // ifdef _MSV_VER
diff --git a/neo/libs/zlib/trees.c b/neo/libs/zlib/trees.c
index b9c72b4c..1cbe076c 100644
--- a/neo/libs/zlib/trees.c
+++ b/neo/libs/zlib/trees.c
@@ -35,6 +35,7 @@
 /* #define GEN_TREES_H */
 
 #include "deflate.h"
+#include "idlib/sys/sys_defines.h"
 
 #ifdef DEBUG
 #  include <ctype.h>
@@ -940,17 +941,9 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
         /* Determine the best encoding. Compute the block lengths in bytes. */
         opt_lenb = (s->opt_len+3+7)>>3;
         static_lenb = (s->static_len+3+7)>>3;
-// RB begin
-#ifdef _MSC_VER
-		Tracev((stderr, "\nopt %Iu(%Iu) stat %Iu(%Iu) stored %Iu lit %u ",
+        Tracev((stderr, "\nopt %" PRIuSIZE "(%" PRIuSIZE ") stat %" PRIuSIZE "(%" PRIuSIZE ") stored %" PRIuSIZE " lit %u ",
                 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
                 s->last_lit));
-#else
-        Tracev((stderr, "\nopt %zu(%zu) stat %zu(%zu) stored %zu lit %u ",
-                opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
-                s->last_lit));
-#endif
-// RB end
         if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
 
     } else {
@@ -1009,7 +1002,7 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
     Tracev((stderr,"\ncomprlen %Iu(%Iu) ", s->compressed_len>>3,
            s->compressed_len-7*last));
 #else
-	Tracev((stderr,"\ncomprlen %zu(%zu) ", s->compressed_len>>3,
+	Tracev((stderr,"\ncomprlen %" PRIuSIZE "(%" PRIuSIZE ") ", s->compressed_len>>3,
            s->compressed_len-7*last));
 #endif
 // RB end