Partially roll back upstream commit 4711119089e1ad08dad206f4fded68f1972fdeed
since released versions of uClibc don't support isfdtype().

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

diff -Nura acpid-2.0.22.orig/sock.c acpid-2.0.22/sock.c
--- acpid-2.0.22.orig/sock.c	2014-04-22 18:04:19.706841764 -0300
+++ acpid-2.0.22/sock.c	2014-04-22 18:05:08.285479625 -0300
@@ -53,7 +53,10 @@
 int
 is_socket(int fd)
 {
-    return (isfdtype(fd, S_IFSOCK) == 1);
+	int v;
+	socklen_t l = sizeof(int);
+
+	return (getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
 }
 
 /* accept a new client connection */