--- modules/mappers/mod_rewrite.c	2010-06-28 16:29:58.000000000 +0100
+++ modules/mappers/mod_rewrite.c.orig	2010-06-11 22:14:19.000000000 +0100
@@ -2387,11 +2387,7 @@
 
     while (env) {
         name = do_expand(env->data, ctx, NULL);
-        if (*name == '!') {
-            *name++ = '\0';
-            apr_table_unset(ctx->r->subprocess_env, name);
-            rewritelog((ctx->r, 5, NULL, "unsetting env variable '%s'", name));
-        } else if ((val = ap_strchr(name, ':')) != NULL) {
+        if ((val = ap_strchr(name, ':')) != NULL) {
             *val++ = '\0';
 
             apr_table_set(ctx->r->subprocess_env, name, val);