Makefile 'if' condition with regexp

I need to do something like this:

case `uname -m` in
i?86) echo "CFLAGS += -march=i486 -mtune=native" > configparms ;;
esac

But I need to do this in makefile for a particular target. I have not found a method to make an if condition with a regular expression.

I tried this:

ifeq ($(shell uname -m), i*86)

But it does not work. Even

ifeq ($(shell uname -m), i686)

does not work.