diff --git a/include/builtin32.h b/include/builtin32.h
index 4edb4857da3..87197567f9f 100644
--- a/include/builtin32.h
+++ b/include/builtin32.h
@@ -12,6 +12,7 @@ typedef void (*ENTRYPOINT32)();
 typedef struct
 {
     const char           *name;         /* DLL name */
+    const char*           filename;     /* DLL file name */
     int                   base;         /* Ordinal base */
     int                   nb_funcs;     /* Number of functions */
     int                   nb_names;     /* Number of function names */
diff --git a/tools/build.c b/tools/build.c
index 30759e22fe8..65e710646bb 100644
--- a/tools/build.c
+++ b/tools/build.c
@@ -1222,6 +1222,7 @@ static int BuildSpec32File( char * specfile, FILE *outfile )
     fprintf( outfile, "const BUILTIN32_DESCRIPTOR %s_Descriptor =\n{\n",
              DLLName );
     fprintf( outfile, "    \"%s\",\n", DLLName );
+    fprintf( outfile, "    \"%s\",\n", DLLFileName );
     fprintf( outfile, "    %d,\n", Base );
     fprintf( outfile, "    %d,\n", Limit - Base + 1 );
     fprintf( outfile, "    %d,\n", nb_names );