configure.ac: uclinux is also linux

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

diff -Nura igmpproxy-0.1.orig/configure.ac igmpproxy-0.1/configure.ac
--- igmpproxy-0.1.orig/configure.ac	2014-03-12 18:43:02.369323771 -0300
+++ igmpproxy-0.1/configure.ac	2014-03-12 18:43:22.129979179 -0300
@@ -7,7 +7,7 @@
 
 AC_CANONICAL_HOST
 case $host_os in
-	linux*) os=linux;;
+	linux*|uclinux*) os=linux;;
 	freebsd*) os=freebsd;;
 	netbsd*) os=netbsd;;
 	openbsd*) os=openbsd;;