Fix MSVC6 warnings. (spotted by Tim Peters)
diff --git a/Modules/cjkcodecs/_gb2312.c b/Modules/cjkcodecs/_gb2312.c
index 388f0b8..7659860 100644
--- a/Modules/cjkcodecs/_gb2312.c
+++ b/Modules/cjkcodecs/_gb2312.c
@@ -17,7 +17,7 @@
         DBCHAR      code;
 
         if (c < 0x80) {
-            WRITE1(c)
+            WRITE1((unsigned char)c)
             NEXT(1, 1)
             continue;
         }