Do not build redis on CI by default

Makefile

@@ -80,6 +80,7 @@ endif
 endif
 
 redis:
+ifneq ($(redis), on)
 ifneq ($(arch), riscv64)
 ifneq ($(shell uname), Darwin)
 	mkdir -p $(out_dir)
@@ -88,6 +89,7 @@ ifneq ($(shell uname), Darwin)
 	@cp redis/build/$(arch)/redis-cli $(out_dir)/redis-cli
 endif
 endif
+endif
 
 build: rust ucore biscuit $(busybox) nginx redis
 

README.md

@@ -35,12 +35,12 @@ Output to `build/$(arch)`
 ## Support matrix
 
 |                             | x86_64 | aarch64 | riscv32 | riscv64 |
-| ------- | ------ | ------- | ------- | ------- |
+| --------------------------- | ------ | ------- | ------- | ------- |
 | ucore                       | n      | y       | y       | y       |
 | rust                        | y      | y       | y       | y       |
 | biscuit                     | y      | y       | n       | y       |
 | nginx                       | y      | y       | n       | y       |
-| redis   | y      | y       | y       | n       |
+| redis (build with redis=on) | y      | y       | y       | n       |
 | busybox                     | y      | y       | n       | y       |