Enable test only if CONFIG_FEATURE_GREP_EGREP_ALIAS is defined.
diff --git a/testsuite/grep/egrep-supports-extended-regexps b/testsuite/grep/egrep-supports-extended-regexps
index 8db154c..f858e84 100644
--- a/testsuite/grep/egrep-supports-extended-regexps
+++ b/testsuite/grep/egrep-supports-extended-regexps
@@ -1 +1,2 @@
+# UNSUPPORTED: CONFIG_FEATURE_GREP_EGREP_ALIAS
 test x`echo foo | busybox egrep fo+` = xfoo