More Windows warning fixes.

js/src/js.c

@@ -2459,7 +2459,7 @@ snarf(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
         buf = JS_malloc(cx, len + 1);
         if (!buf) {
             ok = JS_FALSE;
-        } else if ((cc = read(fd, buf, len)) != len) {
+        } else if ((size_t)(cc = read(fd, buf, len)) != len) {
             JS_free(cx, buf);
             JS_ReportError(cx, "can't read %s: %s", pathname,
                            (cc < 0) ? strerror(errno) : "short read");

js/src/jsgc.c

@@ -785,7 +785,8 @@ JSBool
 js_LockGCThingRT(JSRuntime *rt, void *thing)
 {
     JSBool ok, deep;
-    uint8 *flagp, flags, lock, type;
+    uint8 *flagp;
+    uintN flags, lock, type;
     JSGCLockHashEntry *lhe;
 
     ok = JS_TRUE;