diff --git a/polymer/eduke32/build/include/compat.h b/polymer/eduke32/build/include/compat.h
index 2d141fb3b..625e50914 100644
--- a/polymer/eduke32/build/include/compat.h
+++ b/polymer/eduke32/build/include/compat.h
@@ -289,6 +289,10 @@ static inline float nearbyintf(float x)
 # error Unknown endianness
 #endif
 
+#if defined _LP64 || defined __LP64__ || defined __64BIT__ || _ADDR64 || defined _WIN64 || defined __arch64__ || __WORDSIZE == 64 || (defined __sparc && defined __sparcv9) || defined __x86_64 || defined __amd64 || defined __x86_64__ || defined __amd64__ || defined _M_X64 || defined _M_IA64 || defined __ia64 || defined __IA64__
+# define BITNESS64
+#endif
+
 #ifdef EXTERNC
 
 # ifndef SCREWED_UP_CPP
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index 547866d48..28976f67d 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -8885,7 +8885,16 @@ int32_t ExtPreInit(int32_t argc,const char **argv)
 
     OSD_SetLogFile("mapster32.log");
     OSD_SetVersion("Mapster32" " " VERSION,0,2);
-    initprintf("Mapster32 %s %s\n", VERSION, s_buildRev);
+    initprintf("Mapster32 %s %s"
+#ifdef BITNESS64
+        " (64-bit)"
+#else
+        " (32-bit)"
+#endif
+#ifdef __cplusplus
+        " C++ build"
+#endif
+        "\n", VERSION, s_buildRev);
     initprintf("Compiled %s\n", __DATE__" "__TIME__);
     //    initprintf("Copyright (c) 2008 EDuke32 team\n");
 
diff --git a/polymer/eduke32/source/game.c b/polymer/eduke32/source/game.c
index 1315c39c3..e7c2ad5d6 100644
--- a/polymer/eduke32/source/game.c
+++ b/polymer/eduke32/source/game.c
@@ -11210,13 +11210,16 @@ int32_t app_main(int32_t argc, const char **argv)
 
     wm_setapptitle(APPNAME);
 
-    initprintf(HEAD2 " %s %s\n", s_buildRev,
-#ifdef __cplusplus
-        "C++ build"
+    initprintf(HEAD2 " %s"
+#ifdef BITNESS64
+        " (64-bit)"
 #else
-        ""
+        " (32-bit)"
 #endif
-        );
+#ifdef __cplusplus
+        " C++ build"
+#endif
+        "\n", s_buildRev);
     initprintf("Compiled %s\n", __DATE__" "__TIME__);
 
     if (!usecwd)