diff --git a/polymer/eduke32/Makefile b/polymer/eduke32/Makefile
index 25ffe7335..53cb7b588 100644
--- a/polymer/eduke32/Makefile
+++ b/polymer/eduke32/Makefile
@@ -103,6 +103,7 @@ JMACTOBJ=$(OBJ)/file_lib.$o \
 GAMEOBJS=$(OBJ)/game.$o \
 	$(OBJ)/actors.$o \
 	$(OBJ)/anim.$o \
+	$(OBJ)/common.$o \
 	$(OBJ)/config.$o \
 	$(OBJ)/demo.$o \
 	$(OBJ)/gamedef.$o \
@@ -124,6 +125,7 @@ GAMEOBJS=$(OBJ)/game.$o \
 	$(JMACTOBJ)
 
 EDITOROBJS=$(OBJ)/astub.$o \
+	$(OBJ)/common.$o \
 	$(OBJ)/m32def.$o \
 	$(OBJ)/m32exec.$o \
 	$(OBJ)/m32vars.$o \
diff --git a/polymer/eduke32/build/include/common.h b/polymer/eduke32/build/include/common.h
new file mode 100644
index 000000000..36f62efad
--- /dev/null
+++ b/polymer/eduke32/build/include/common.h
@@ -0,0 +1,27 @@
+//
+// Definitions of common non-engine data structures/functions
+// (and declarations of data appearing in both)
+// for EDuke32 and Mapster32
+//
+
+#ifndef EDUKE32_COMMON_H_
+#define EDUKE32_COMMON_H_
+
+
+//// TYPES
+struct strllist
+{
+    struct strllist *next;
+    char *str;
+};
+
+
+//// EXTERN DECLS
+extern struct strllist *CommandPaths, *CommandGrps;
+
+
+//// FUNCTIONS
+void G_AddGroup(const char *buffer);
+void G_AddPath(const char *buffer);
+
+#endif
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index 10aad0054..2ce86cc21 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -31,6 +31,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include "osdfuncs.h"
 #include "names.h"
 
+#include "common.h"
 #include "mapster32.h"
 #include "keys.h"
 
@@ -120,13 +121,6 @@ static int32_t lastupdate, mousecol, mouseadd = 1, bstatus;
 static int32_t usecwd = 0;
 #endif
 
-static struct strllist
-{
-    struct strllist *next;
-    char *str;
-}
-*CommandPaths = NULL, *CommandGrps = NULL;
-
 const char *scripthist[SCRIPTHISTSIZ];
 int32_t scripthistend = 0;
 
@@ -8384,47 +8378,6 @@ static void G_ShowParameterHelp(void)
 }
 
 
-// CODEDUP game.c
-static void G_AddPath(const char *buffer)
-{
-    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
-    s->str = Bstrdup(buffer);
-
-    if (CommandPaths)
-    {
-        struct strllist *t;
-        for (t = CommandPaths; t->next; t=t->next) ;
-        t->next = s;
-        return;
-    }
-
-    CommandPaths = s;
-}
-
-// CODEDUP game.c
-static void G_AddGroup(const char *buffer)
-{
-    char buf[BMAX_PATH];
-
-    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
-
-    Bstrcpy(buf, buffer);
-
-    if (Bstrchr(buf,'.') == 0)
-        Bstrcat(buf,".grp");
-
-    s->str = Bstrdup(buf);
-
-    if (CommandGrps)
-    {
-        struct strllist *t;
-        for (t = CommandGrps; t->next; t=t->next) ;
-        t->next = s;
-        return;
-    }
-    CommandGrps = s;
-}
-
 #define COPYARG(i) \
     Bmemcpy(&testplay_addparam[j], argv[i], lengths[i]); \
     j += lengths[i]; \
diff --git a/polymer/eduke32/source/common.c b/polymer/eduke32/source/common.c
new file mode 100644
index 000000000..d9cc3c8a5
--- /dev/null
+++ b/polymer/eduke32/source/common.c
@@ -0,0 +1,48 @@
+//
+// Common non-engine code/data for EDuke32 and Mapster32
+//
+
+#include "compat.h"
+
+#include "common.h"
+
+
+struct strllist *CommandPaths, *CommandGrps;
+
+void G_AddGroup(const char *buffer)
+{
+    char buf[BMAX_PATH];
+
+    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
+
+    Bstrcpy(buf, buffer);
+
+    if (Bstrchr(buf,'.') == 0)
+        Bstrcat(buf,".grp");
+
+    s->str = Bstrdup(buf);
+
+    if (CommandGrps)
+    {
+        struct strllist *t;
+        for (t = CommandGrps; t->next; t=t->next) ;
+        t->next = s;
+        return;
+    }
+    CommandGrps = s;
+}
+
+void G_AddPath(const char *buffer)
+{
+    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
+    s->str = Bstrdup(buffer);
+
+    if (CommandPaths)
+    {
+        struct strllist *t;
+        for (t = CommandPaths; t->next; t=t->next) ;
+        t->next = s;
+        return;
+    }
+    CommandPaths = s;
+}
diff --git a/polymer/eduke32/source/game.c b/polymer/eduke32/source/game.c
index c030f2301..24762a540 100644
--- a/polymer/eduke32/source/game.c
+++ b/polymer/eduke32/source/game.c
@@ -51,6 +51,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include "savegame.h"
 #include "anim.h"
 #include "demo.h"
+#include "common.h"
 
 #ifdef LUNATIC_ENABLE
 # include "lunatic.h"
@@ -91,13 +92,6 @@ static char *CommandMap = NULL;
 static char *CommandName = NULL;
 int32_t g_forceWeaponChoice = 0;
 
-static struct strllist
-{
-    struct strllist *next;
-    char *str;
-}
-*CommandPaths = NULL, *CommandGrps = NULL;
-
 char boardfilename[BMAX_PATH] = {0}, currentboardfilename[BMAX_PATH] = {0};
 
 static char g_rootDir[BMAX_PATH];
@@ -8571,47 +8565,6 @@ static int32_t loaddefinitions_game(const char *fn, int32_t preload)
 }
 
 
-// CODEDUP astub.c
-static void G_AddGroup(const char *buffer)
-{
-    char buf[BMAX_PATH];
-
-    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
-
-    Bstrcpy(buf, buffer);
-
-    if (Bstrchr(buf,'.') == 0)
-        Bstrcat(buf,".grp");
-
-    s->str = Bstrdup(buf);
-
-    if (CommandGrps)
-    {
-        struct strllist *t;
-        for (t = CommandGrps; t->next; t=t->next) ;
-        t->next = s;
-        return;
-    }
-    CommandGrps = s;
-}
-
-// CODEDUP astub.c
-static void G_AddPath(const char *buffer)
-{
-    struct strllist *s = Bcalloc(1,sizeof(struct strllist));
-    s->str = Bstrdup(buffer);
-
-    if (CommandPaths)
-    {
-        struct strllist *t;
-        for (t = CommandPaths; t->next; t=t->next) ;
-        t->next = s;
-        return;
-    }
-    CommandPaths = s;
-}
-
-
 static void G_CheckCommandLine(int32_t argc, const char **argv)
 {
     int16_t i = 1, j;